=Paper= {{Paper |id=Vol-3159/T6-1 |storemode=property |title=Findings of the Sentiment Analysis of Dravidian Languages in Code-Mixed Text |pdfUrl=https://ceur-ws.org/Vol-3159/T6-1.pdf |volume=Vol-3159 |authors=Bharathi Raja Chakravarthi,Ruba Priyadharshini,Sajeetha Thavareesan,Dhivya Chinnappa,Durairaj Thenmozhi,Elizabeth Sherly,John P. McCrae,Adeep Hande,Rahul Ponnusamy,Shubhanker Banerjee,Charangan Vasantharajan |dblpUrl=https://dblp.org/rec/conf/fire/ChakravarthiPTC21 }} ==Findings of the Sentiment Analysis of Dravidian Languages in Code-Mixed Text== https://ceur-ws.org/Vol-3159/T6-1.pdf
Findings of the Sentiment Analysis of Dravidian
Languages in Code-Mixed Text
Bharathi Raja Chakravarthia , Ruba Priyadharshinib , Sajeetha Thavareesanc ,
Dhivya Chinnappad , Durairaj Thenmozhie , Elizabeth Sherlyf , John P. McCraea ,
Adeep Handeh , Rahul Ponnusamyf , Shubhanker Banerjeej and
Charangan Vasantharajank
a
  Insight SFI Research Centre for Data Analytics, Data Science Institute, National University of Ireland Galway
b
  ULTRA Arts and Science College, Madurai, Tamil Nadu, India
c
  Eastern University, Sri Lanka
d
  Thomson Reuters, USA
e
  Sri Sivasubramaniya Nadar College of Engineering, Tamil Nadu, India
f
  Indian Institute of Information Technology and Management-Kerala, India
h
  Indian Institute of Information Technology Tiruchirappalli
j
  ADAPT Centre, Data Science Institute, National University Of Ireland Galway
k
  Department of Computer Science and Engineering, University of Moratuwa, Sri Lanka


                                         Abstract
                                         We present the results of the Dravidian-CodeMix shared task1 held at FIRE 2021, a track on sentiment
                                         analysis for Dravidian Languages in Code-Mixed Text. We describe the task, its organization, and the
                                         submitted systems. This shared task is the continuation of last year’s Dravidian-CodeMix shared task2
                                         held at FIRE 2020. This year’s tasks included code-mixing at the intra-token and inter-token levels.
                                         Additionally, apart from Tamil and Malayalam, Kannada was also introduced. We received 22 systems
                                         for Tamil-English, 15 systems for Malayalam-English, and 15 for Kannada-English. The top system
                                         for Tamil-English, Malayalam-English and Kannada-English scored weighted average F1-score of 0.711,
                                         0.804, and 0.630, respectively. In summary, the quality and quantity of the submission show that there
                                         is great interest in Dravidian languages in code-mixed setting and state of the art in this domain still
                                         needs more improvement.

                                         Keywords
                                         Sentiment analysis, Dravidian languages, Tamil, Malayalam, Kannada, Code-mixing,




                  1
      https://dravidian-codemix.github.io/2021/index.html/
                  2
      https://dravidian-codemix.github.io/2020/index.html/
FIRE 2021: Forum for Information Retrival Evaluation, December 13-17, 2021, India
" bharathi.raja@insight-centre.org (B.R. Chakravarthi); rubapriyadharshini.a@gmail.com (R. Priyadharshini);
sajeethas@esn.ac.lk (S. Thavareesan); dhivya.infant@gmail.com (D. Chinnappa); theni_d@ssn.edu.in (D.
Thenmozhi); sherly@iiitmk.ac.in (E. Sherly); john.mccrae@insight-centre.org (J.P. McCrae); adeeph18c@iiitt.ac.in
(A. Hande); rahul.mi20@iiitmk.ac.in (R. Ponnusamy); S.Banerjee3@nuigalway.ie (S. Banerjee);
charangan.18@cse.mrt.ac.lk (C. Vasantharajan)
 0000-0002-4575-7934 (B.R. Chakravarthi); 0000-0003-2323-1701 (R. Priyadharshini); 0000-0002-6252-5393 (S.
Thavareesan); 0000-0002-8318-3337 (D. Chinnappa); 0000-0001-6508-950X (E. Sherly); 0000-0002-7227-1331 (J.P.
McCrae); 0000-0002-2003-4836 (A. Hande); 0000-0001-8023-7742 (R. Ponnusamy); 0000-0002-3969-5183 (S.
Banerjee); 0000-0001-7874-3881 (C. Vasantharajan)
                                       © 2021 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
    CEUR
    Workshop
    Proceedings
                  http://ceur-ws.org
                  ISSN 1613-0073       CEUR Workshop Proceedings (CEUR-WS.org)
1. Introduction
Sentiment analysis is a text mining task that finds and extracts personal information from the
source material, allowing a company/researcher to understand better the social sentiment of
its brand, product, or service while monitoring online conversations [1]. In our case, we used
the comments from the movie trailer, so it is about finding the viewers sentiment of the movie.
The constantly increasing number of social media and user-generated comments raises the
importance of finding sentiments in local languages as making these predictions is essential
for local businesses. For this study, we created data in Dravidian languages, namely Tamil
(ISO 639-3:tam), Malayalam (ISO 639-3:mal), and Kannada (ISO 639-3:kan). Tamil is the official
language of Tamil Nadu, the Indian Union, Sri Lanka, Malaysia and is spoken in many places
in South Asian countries. Malayalam and Kannada have official status in the Indian Union
government and the state of Kerala and Karnataka, respectively [2, 3].
   The Tamil script, the Vatteluttu alphabet, and the Chola-Pallava script all came together to
form the Tamil script. The Tamil script dates back to 600 BCE, found at various archaeolog-
ical sites in Tamil Nadu, Sri Lanka, Egypt, Thailand, Vietnam, Cambodia and Indonesia. The
Chola-Pallava script is the ancestor of the present Tamil script. Thani Tamil Iyakkam (Pure
or Independent Tamil Movement) is a Tamil linguistic purity movement that tried to avoid
borrowing terms from Sanskrit, English, and other languages in 1916. Maraimalai Adigal1 ,
Paventhar Bharathidasan2 , Devaneya Pavanar3 , and Pavalareru Perunchitthiranaar4 started the
movement, which was spread through the Thenmozhi literary journal created by Pavalareru P.
The natural continuation of this endeavour was to purge Tamil of Sanskrit influence including
negative societal attitudes such discrimination based on colour and birth, central discrimina-
tion being education only for particular people which denies education for the main population
that they felt kept Tamils in a condition of economic, cultural, and political slavery, which they
believed made Tamil and other Dravidian states vulnerable to external political dominance.
   Despite the vast amounts of primary and secondary speakers, Kannada is a low resource lan-
guage concerning language technology. It primarily speaks by people in Karnataka, India, and
is also the state’s official language. Catanese, the Kannada script, is an alpha-syllabary of the
scripts of the Brahmic family evolving into the Kadamba script and used to write other under-
resourced languages like Tulu, Konkani, and Sankethi. The Kannada script has 13 vowels (14 if
the obsolete vowel includes), 34 consonants, and 2 yogavahakas (semiconsonants: part-vowel,
part-consonant). Malayalam used Vatteluttu script and Pallava-Grantha script. However, by
2020 language mixing of foreign languages in the Dravidian language has become very fre-
quent. English is seen as a predominant language economically and culturally by Dravidian
languages speakers, so social media users often adopted Roman script and mixed native script.
   The Dravidian-CodeMix task was introduced in 2020 and aimed to explore the sentiment
analysis of code mixed comments in Dravidian languages. In 2020, we released the data for
Tamil and Malayalam in Roman script. The dataset included 15,000 instances for Tamil and
6,000 instances for Malayalam. In 2021, apart from Tamil and Malayalam, we introduce a Sen-
   1
     https://en.wikipedia.org/wiki/Maraimalai_Adigal
   2
     https://en.wikipedia.org/wiki/Bharathidasan
   3
     https://en.wikipedia.org/wiki/Devaneya_Pavanar
   4
     https://en.wikipedia.org/wiki/Perunchithiranar_(Tamil_nationalist)
timent Analysis dataset for Kannada Thus, in 2021 we will include three languages Tamil,
Malayalam, and Kannada. Our dataset contains all kinds of code-mixing, ranging from simple
script mixing to mixing at the morphological level. The challenge is to determine the polarity of
sentiment in a code-mixed dataset of comments or posts in Tamil-English, Malayalam-English,
and Kannada-English [4]. More details about the annotation of the dataset can be found in
[3, 5, 6]
   Our shared task seeks to promote a study on how sentiment communicates on Dravidian
social media language in a code-mixed setting and aim for better social media analysis [7, 8].
We presented the training, development and test set to the participants. This paper presents
an overview of the task description, dataset, description of the participating systems, analysis,
and provide insights from the shared task.


2. Task Description
This task aims at the classification of sentence-level polarities. The main objective of the pro-
posed systems is to classify the polarity of a given YouTube comment into mixed feelings,
negative and positive or identify if the given comment does not belong to one of the following
languages of this shared task: Tamil-English, Malayalam-English, and Kannada-English. The
comments provided to the participants were written in a mixture of Latin script, native script,
and both Latin script and native script. Some of the comments followed the grammar of one of
the Dravidian languages: Tamil or Malayalam, or Kannada, but are written using the English
lexicon. Other comments followed the lexicon of the Dravidian languages and were written
using English grammar. The participants were provided with the development, training and
test dataset. This is a message-level polarity classification task. Participants’ systems have
to classify a Youtube comment into positive, negative, neutral, mixed emotions, or not in the
intended languages.
   The following examples are from the Tamil dataset illustrate dataset code-mixing.

    • Epo pa varudhu indhe padam - When will this movie come out? Tamil words written
      in Roman script with no English switch.

    • Yaru viswasam teaser ku marana waiting like pannunga - Who is waiting for Viswarm
      teaser, please like Tag switching with English words.

    • Omg .. use head phones. Enna bgm da saami .. - OMG! Use your headphones. Good
      Lord, What a background score! Inter-sentential switch

    • I think sivakarthickku hero getup set aagala. - I think the hero role does not suit
      Sivakarthick. Intra-sentential switch between clauses.

  The following examples are from the Malayalam dataset.

    • Orupaadu nalukalku shesham aanu ithupoloru padam eranghunnathu. - A movie
      like this is coming out after a long time. Malayalam words written in Roman script with
      no English switch.
 • Malayalam industry ku thriller kshamam illannu kaanichu kodukku anghotu. -
   Show that there is no shortage for thriller movies in Malayalam film industry. Tag switching
   with English words.

 • Manju chechiyude athyugran performancenayi kaathirikunnu. The Lady su-
   perstar of Malayalam industry. - Waiting for the awesome performance of Manju sister.
   The Lady superstar of Malayalam film industry. Inter-sentential switch

 • Next movie ready for nammude swantham dhanush. - Next movie ready for our
   dear Dhanush.

 • Orupaadu nalukalku shesham aanu ithupoloru padam eranghunnathu. - A movie
   like this is coming out after a long time. Malayalam words are written in Roman script
   with no English switch.

The following examples are from the Kannada dataset.

 • Yaru tension agbede yakandre dislike madiravru mindrika kadeyavru – No one
   needs to worry as the people who disliked this are fans of Mandrika. Intra-sentential switch
   between clauses

 • Gottilla Rakshit Shettru natana nanu fida. Boss waiting for movie Charitre
   bareyo ella lakshana ide. All the best for you bright future –Don’t know why,
   I am obsessed with Rakshit Shetty’s acting. waiting for your movie, expecting it to be a
   blockbuster. All the best for your bright future. Inter-sentential and intra-sentential mix.
   (Kannada written in both Latin and Kannada script)

 • Nanage ansutte ee video vanna rashmika mandanna fans dislike madirbahudu
   –I feel that this video has been disliked by the fans of Rashmika Mandana.Intra-sentential
   switch between clauses.Code-switching at morphological level: (written in both Kannada
   and Latin script)

 • My favorite song in 2019 is Taaja Samachara. Sahitya priyare omme ee haadu
   kelidre kelthane irabeku ansutte. Everybody watch this. –My favourite song in 2019
   is Taaja Sanachara. Literature admirers, please listen to the song once; you would want to
   listen to it over and over again. Everybody watch this. Inter-sentential code-mixing: Mix
   of English and Kannada (Kannada written in Kannada script itself)

The data was annotated for sentiments according to the following schema.

 • Positive state: The text contains an explicit or implicit indication that the speaker is in
   an optimistic mood, i.e., joyful, admiring, relaxed, and forgiving.

 • Negative state: The text contains an explicit or implicit indication that the speaker is
   in an unfavourable condition, i.e., depressed, angry, nervous, or aggressive.

 • Mixed feelings: The text contains an explicit or implicit indication indicating that the
   speaker is experiencing both good and negative emotions. Comparing two films
         Language                                  Tamil Malayalam Kannada
         Number of words                         513,311    224,207  65,002
         Vocabulary size                          94,928     57,566  20,665
         Number of comments                       44,020     19,616   7,671
         Number of sentences                      52,750     24,014   8,472
         Average number of words per sentence         11         11       8
         Average number of sentences per comment       1          1       1
Table 1
Corpus statistics of the dataset



         Class                               Tamil     Malayalam         Kannada
         Negative                  5,228 (11.87 %) 2,600 (13.25 %) 1,484 (19.34 %)
         Not in intended language   2,087 (4.74 %)   1,445 (736 %) 1,136 (14.80 %)
         Neutral state             6,904 (15.68 %) 6,502 (33.14 %)   842 (10.97 %)
         Mixed feelings            4,928 (1119 %) 1,162 (5.92 %)      691 (9.00 %)
         Positive                 24,873 (56.50 %) 7,907 (40.30 %) 3,518 (45.86 %)
         Total                              44,020          19,616           7,671
Table 2
Class-wise Dataset Distribution


                                       Tamil Malayalam Kannada
                          Training    35,220     15,694   6,136
                          Development 4,398       1,960     767
                          Test         4,402      1,962     768
                          Total       44,020     19,616   7,671
Table 3
Train-Development-Test Data Distribution with 90%-5%-5% train-dev-test split



    • Neutral state: There is no explicit or implicit indication of the speaker’s emotional state:
      examples include requests for likes or subscriptions, as well as inquiries about the release
      date or movie dialogue. This is a state that can be termed neutral.

    • Not in intended language: For Kannada, if the sentence does not contain Kannada,
      then it is not Kannada.

The annotators were provided with Tamil, Kannada, and Malayalam translations of the above
to facilitate better understanding. A minimum of three annotators annotated each sentence.
Dataset corpus statistics are given in Table 1, Table 2, and Table 3.
              No.   TeamName                      Precision   Recall   F1-Score    Rank
              1     SSNCSE_NLP [9]                     0.64     0.66       0.63       1
              2     MUCIC [10]                         0.62     0.66       0.63       2
              3     CIA_NITT [11]                      0.63     0.64       0.63       3
              4     SOA-NLP [12]                       0.64     0.65       0.62       4
              5     IIITT-Karthik Puranik [13]         0.62     0.63       0.62       5
              6     Dynamic Duo [14]                   0.67     0.65       0.62       6
              7     KBCNMUJAL [15]                     0.62     0.64       0.62       7
              8     IIITT-Pawan [16]                   0.61     0.61       0.61       8
              9     AI ML                              0.62     0.60       0.61       9
              10    SSN_NLP_MLRG [17]                  0.60     0.59       0.60      10
              11    Amrita_CEN [18]                    0.60     0.58       0.57      11
              12    IIIT_DWD                           0.57     0.54       0.55      12
              13    LogicDojo                          0.43     0.56       0.48      13
              14    MUM [19]                           0.41     0.49       0.37      14
              15    IRLab@IITBHU [20]                  0.29     0.35       0.32      15
Table 4
Rank list based on weighted average F1-score along with other evaluation metrics (Precision and Recall)
for the Kannada track



3. Methodology
We received 54 submissions for the task, out of which 17 were for the Malayalam track, 22 were
for the Tamil track, and 15 were for the Kannada track. The rank lists for the Kannada track,
Tamil track, and the Malayalam track are shown in Tables 4, 5 and 6 respectively. Below we
briefly describe the systems proposed by the top 3 teams in both tracks.

    • MUCIC [28]: The authors extracted the character level and syllable level features from
      the text, which were then used to create the TF-IDF feature vectors. The authors have
      documented three models, namely: a logistic regression model, an LSTM classifier, and
      a multilayer perceptron classifier, to classify the messages. The TF-IDF feature vectors
      are fed to these models, which in turn are trained on the classification task.

    • CIA_NITT [29]: The authors proposed a system that uses a pretrained XLM-RoBERTa for
      sequence classification. They tokenize the input text using the SentencePiece tokenizer,
      which is then fed as embeddings to be fine-tuned for the XLM-RoBERTa model. .

    • ZYBank-AI [30]: The authors based their experiments on the XLM-RoBERTa as well.
      To improve the results, they have added self-attention to the 12 hidden layers of the
      XLMRoBERTA. Furthermore, they propose a two-stage pipeline for the task at hand. In
      the first stage, the model is trained on data from Dravidian-CodeMix-FIRE 2020. In the
      second stage, the pre-trained model is fine-tuned on the Dravidian-CodeMix-FIRE 2021
      and evaluated on test data.

    • IIITT-Pawan [31]: The authors proposed an ensemble of several fine-tuned language
      models for sequence classification: BERT, MuRIL, XLM-RoBERTa, DistilBERT. Each of
              No.   TeamName                      Precision   Recall   F1-Score    Rank
              1     CIA_NITT [11]                      0.71     0.71       0.71       1
              2     ZYBank-AI [21]                     0.68     0.68       0.68       2
              3     IIITT-Pawan [16]                   0.62     0.65       0.63       3
              4     IIITT-Karthik Puranik [13]         0.62     0.64       0.62       4
              5     MUCIC [10]                         0.61     0.64       0.62       5
              6     SOA_NLP [12]                       0.61     0.65       0.62       6
              7     Ryzer [22]                         0.60     0.61       0.60       7
              8     SSN_NLP_MLRG [17]                  0.60     0.61       0.60       8
              9     AIML [23]                          0.60     0.60       0.60       9
              10    KBCNMUJAL [15]                     0.58     0.60       0.59      10
              11    SSNCSE_NLP [9]                     0.60     0.64       0.59      11
              12    KonguCSE                           0.57     0.62       0.57      12
              13    MUM [19]                           0.58     0.62       0.56      13
              14    LogicDojo                          0.54     0.59       0.56      14
              15    IIIT DWD [24]                      0.55     0.56       0.56      15
              16    IIIT Surat [25]                    0.54     0.57       0.55      16
              17    Amrita_CEN [18]                    0.64     0.50       0.53      17
              18    SSN-NLP                            0.62     0.49       0.51      18
              19    DLRF                               0.34     0.58       0.42      19
              20    IRLab@IITBHU [20]                  0.38     0.46       0.41      20
              21    SSNHacML [26]                      0.38     0.45       0.41      21
              22    SSN_IT_NLP [27]                    0.38     0.39       0.38      22
Table 5
Rank list based on weighted average F1-score along with other evaluation metrics (Precision and Recall)
for the Tamil track



      the classifiers is separately trained on training data. During testing, soft voting is em-
      ployed among all of these classifiers to predict the most likely class.

    • SOA_NLP[32]: The authors proposed the following two ensemble models for tackling
      the problem at hand: an ensemble of support vector machine, logistic regression and
      random forest for Kannada-English texts and an ensemble of support vector machine
      and logistic regression for Malayalam-English and Tamil-English texts.

    • SSNCSE_NLP [33]: The authors have carried out experiments with different features
      such as TF-IDF vectors, count vectorizer and contextual transformer embeddings on
      primitive machine learning models.

    • IIIT DWD [34]: The authors used pre-trained Word2Vec word embeddings and a parallel
      RNN model to feed the embeddings into, and have reported their findings on all three
      datasets.

    • IIIT Surat [35]: The authors used several feature extraction and preprocessing techniques
      and then used GLoVe word embeddings and then fed those embeddings to Bi-directional
      Long-Short Term Memory (Bi-LSTM) model for further processing. For Char embedding,
              No.   TeamName                      Precision   Recall   F1-Score    Rank
              1     ZYBank-AI Team [21]                0.80     0.81       0.80       1
              2     CIA_NITT [11]                      0.75     0.76       0.75       2
              3     SOA_NLP [12]                       0.73     0.73       0.73       3
              4     MUCIC [10]                         0.73     0.73       0.73       4
              5     AIML [23]                          0.72     0.72       0.72       5
              6     IIITT-Pawan[16]                    0.71     0.71       0.71       6
              7     KBCNMUJAL [15]                     0.73     0.71       0.71       6
              8     SSN_NLP_MLRG [17]                  0.70     0.71       0.70       7
              9     SSNCSE_NLP [9]                     0.69     0.69       0.69       8
              10    Dynamic Duo [14]                   0.69     0.70       0.69       9
              11    IIITT-Karthik Puranik [13]         0.65     0.67       0.65      10
              12    IRLab@IITBHU [20]                  0.65     0.67       0.65      10
              13    Amrita_CEN [18]                    0.64     0.61       0.62      11
              14    IIIT DWD [24]                      0.62     0.62       0.62      12
              15    IIIT Surat [25]                    0.63     0.63       0.61      13
              16    MUM [19]                           0.62     0.63       0.60      14
              17    LogicDojo                          0.52     0.58       0.55      15
Table 6
Rank list based on weighted average F1-score along with other evaluation metrics (Precision and Recall)
for the Malayalam track



      64 units of Bi-LSTM were used, whereas for processing the words, 32 units of Bi-LSTM
      was used.

    • SSN_NLP_MLRG [36]: The authors experimented with several machine learning algo-
      rithms during the validation process and then fine-tuned the MBERT model to build the
      system and predict the sentiment polarity for the Tamil-English, Malayalam-English, and
      Kannada-English languages.

    • IRLab@IITBHU [37]: The authors examined if the use of meta embeddings such as Fast-
      Text will give an edge over pre-trained embeddings such as mBERT. The authors feed
      meta embeddings into a multiheaded attention based transformer encoder and then over
      a BiLSTM layer and concatenating it with TF-IDF embeddings to obtain the final outputs.

    • Amrita_CEN [38]: The authors implemented three architectures: Deep Neural Network
      (DNN), Bi-LSTM, and finally, Convolution Neural network (CNN) combined to a hybrid
      model for all the three test sets. Additionally, the authors use a class-weight optimization
      technique to handle class imbalance.

    • SSNHacML [39]: The authors proposed an ensemble framework called Ensemble of Con-
      volutional Neural Network and Multi-Head Attention with Bidirectional GRU (ECMAG)
      to map the code-mixed user comments to their corresponding sentiments. The model
      has been tested on the Tamil-English Code mixed dataset. The model takes XLMRoberta
      multilingual sub-word embeddings of the processed text data as input.
    • MUM [40]: The authors converted the text data into feature vectors and then fed it into
      a BiLSTM network. The authors submit their predictions to the code-mixed test sets of
      Kannada, Malayalam, and Tamil.

    • AIML [41]: The authors extracted character-level features from the text. The dense neu-
      ral network then uses the extracted features to classify them into different sentiment
      classes.

    • KBCNMUJAL [42]: The authors presented their systems for all three Dravidian Lan-
      guages (Kannada-English, Tamil-English and Malayalam-English). They use models such
      as Multinomial Bayes (MNB), CNN and neural networks.

    • Dynamic Duo [43]: The authors used a pre-trained language-based Model (BERT), wrapped
      with ktrain (a python library for model training and testing) to train and validate the data.
      The authors present their findings on the code-mixed Kannada-English dataset.

    • Ryzer[44]: The authors used conventional translation and transliteration algorithms to
      convert the corpus into a native Tamil script and then fed the data into pre-trained lan-
      guage models like mBert, ULMFit, DistilBert. Additionally, They tested the approach on
      CNN-BiLSTM and ULMFiT.

    • SSN_IT_NLP [45]: The authors used a conventional machine learning algorithm. The TF-
      IDF features are extracted and used for sentiment classification using a Random Forest
      classifier.

    • SSNCSE_NLP [9]: The authors employed a variety of feature extraction techniques and
      concluded that the count, TF-IDF based vectorization, and multilingual transformer en-
      coding technique performs well on the code-mix polarity labelling task. With these fea-
      tures, and acheived a weighted F1 score of 0.588 for the Tamil-English task, 0.69 for the
      Malayalam-English task and 0.63 for the Kannada-English tasks respectively.


4. Evaluation
The distribution of the sentiment classes is imbalanced in both datasets. This takes into account
the varying degrees of importance of each class in the dataset. We used a classification report
tool from Scikit learn5 .
                                                     𝑇𝑃
                                      Precision =                                              (1)
                                                   𝑇𝑃 + 𝐹𝑃
                                                             𝑇𝑃
                                               Recall =                                               (2)
                                                           𝑇𝑃 + 𝐹𝑁
                                                        Precision ∗ Recall
                                      F-Score = 2 ∗                                                   (3)
                                                        Precision + Recall


   5
       https://scikit-learn.org/stable/modules/generated/sklearn.metrics.classification_report.html
                                          𝐿
                              𝑃weighted = ∑(𝑃 of 𝑖 × Weight of 𝑖)                             (4)
                                          𝑖=1

                                           𝐿
                              𝑅weighted = ∑(𝑅 of 𝑖 × Weight of 𝑖)                             (5)
                                          𝑖=1

                                           𝐿
                     𝐹 − 𝑆𝑐𝑜𝑟𝑒weighted = ∑(𝐹 − 𝑆𝑐𝑜𝑟𝑒 of 𝑖 × Weight of 𝑖)                      (6)
                                          𝑖=1


5. Results and Discussion
The sentiment analysis shared task was organized for three languages Tamil, Kannada, and
Malayalam. Overall, there are 120 participants registered for this shared task, yet 22 teams
have submitted their working notes for Tamil, 17 for Malayalam, and 15 for Kannada.Table 4,
Table 5, and Table 6 show the rank lists of Tamil, Malayalam and Kannada in that order. Most
of the submissions submit their systems for the three languages, as specified earlier. Here in
this section, we highlight the results of all three languages, which have ranked top positions
on the dataset. The results are sorted based on the weighted F1 scores. Most of the teams have
used transformer-based models such as BERT, DistilBERT, XLM-RoBERTa or other language
models that follow its architecture, in spite of not being pretrained on code-mixed text. Due to
the presence of a non-native script in our corpus, the teams got the pre-trained model from the
libraries and adopted it for our corpus by fine-tuning. Some teams have used Long Short Term
Memory (LSTM) and ULMFiT in their experiments. Also, a few other submissions adopted
traditional machine learning algorithms such as Naive Bayes (NB), K-Nearest Neighbors, etc.,
to solve the problem.
   However, LSTM and traditional machine learning algorithms did not yield good results com-
pared to the transformer-based models. Out of all the proposed models, XLM-RoBERTa and the
transformer-based model produced the best outcomes. Even though many systems with dif-
ferent approaches with F1-score less than the baseline, we accepted those papers to encourage
diverse research methods to solve the problem in Dravidian Languages. Most working notes
reported class-wise precision, recall, and F1-score. We used weighted F1 scores as our primary
evaluation metric.
   Among the Tamil teams, CIA_NITT [29] got the first position with an F1-score of 0.71. This
system achieved 0.71 as the precision and recall score is the same as the F-score. The team
from ZYBank-AI [21] achieved the second position with an F-score of 0.68, lagging the top by
0.03. The top five teams attained an F1 score higher than 0.62. Teams placed in the top positions
utilized the transformer-based models for their experiments, particularly XLM-RoBERTa. Con-
textual embeddings are also found to be effective in this method to reach the top positions. In
Malayalam, ZYBank-AI [21] and CIA_NITT [29] teams switched positions with an F1-score of
080 and 0.75, respectively. Team IIITT-Pawan [31] reached the third position with an F1-score
of 0.63 and lagged the top team by only 0.08. According to the Kannada benchmark, CIA_NITT
[29] secured the third position while SSNCSE_NLP [33] and MUCIC [28] teams reached first
                           Language    Team Name               Rank
                                       CIA_NITT [29]           1
                           Tamil       ZYBank-AI [21]          2
                                       IIITT-Pawan [31]        3
                                       SSNCSE_NLP [33]         1
                           Kannada     MUCIC [28]              2
                                       CIA_NITT [29]           3
                                       ZYBank-AI Team [21]     1
                           Malayalam   CIA_NITT [29]           2
                                       SOA_NLP [32]            3
Table 7
Overall Results with Top Three Ranks



and second places in the benchmark, respectively. Also, both teams have used traditional ma-
chine learning algorithms such as Logistic Regression, SVM with TF-IDF feature vectors. As we
can see, these models have overcome the transformer-based models based on the performance
and became the best in the Kannada benchmark.
   Table 7 shows the overall results and teams that are placed in the top three positions. As
we can see, only one team(CIA_NITT [29]) managed to be in the top 3 systems for the lan-
guages, along with achieving the best performance on the code-mixed Tamil dataset. Among
the systems submitted during the evaluation period, we observe that the best performing mod-
els scored a weighted F1-score of 0.63 in Kannada, 0.80 in Malayalam, and 0.71 in Tamil.


6. Conclusion
We present the results of the sentiment analysis shared task on Tamil, Malayalam, and Kan-
nada. The dataset used in the shared tasks included code-mixed instances obtained from social
media. Specifically, the dataset was created from Youtube comments following human anno-
tation. Most of the participants fine-tuned pretrained multilingual language models. At the
same time, the top-performing systems involved the application of attention layers on the con-
textualized word embeddings and fine-tuning the models pretrained on the previous edition,
DravidianCodeMix-2020’s training data. Results indicate that there is room for improvement
in all three languages Tamil, Malayalam, and Kannada. The increase in the number of partic-
ipants and the better performance of the systems shows an increase in interest in Dravidian
NLP.


Acknowledgments
This publication is the outcome of the research supported in part by a research grant from Sci-
ence Foundation Ireland (SFI) under Grant Number SFI/12/RC/2289_P2 (Insight_2), and Irish
Research Council grant IRCLA/2017/129 (CARDAMOM-Comparative Deep Models of Lan-
guage for Minority and Historical Languages).
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