=Paper= {{Paper |id=Vol-2563/aics_30 |storemode=property |title=Mitigation of Unintended Biases against Non-Native English Texts in Sentiment Analysis |pdfUrl=https://ceur-ws.org/Vol-2563/aics_30.pdf |volume=Vol-2563 |authors=Alina Zhiltsova,Simon Caton,Catherine Mulway |dblpUrl=https://dblp.org/rec/conf/aics/ZhiltsovaCM19 }} ==Mitigation of Unintended Biases against Non-Native English Texts in Sentiment Analysis== https://ceur-ws.org/Vol-2563/aics_30.pdf
    Mitigation of Unintended Biases against
 Non-Native English Texts in Sentiment Analysis

              Alina Zhiltsova1 , Simon Caton2 , and Catherine Mulwa1
               1
                 School of Computing, National College of Ireland, Ireland
              x18121900@student.ncirl.ie, alinazhiltsova@gmail.com,
                              catherine.mulwa@ncirl.ie
    2
      School of Computer Science and Informatics, University College Dublin, Ireland
                                 simon.caton@ucd.ie



         Abstract. Currently the demand for text analytics grows due to the fact
         that textual data is being created online in large amounts. A number of
         tools are available for various tasks related to natural language process-
         ing such as sentiment analysis and text pre-processing. The majority of
         these tools are trained using unrepresentative data, which may lead to
         unintended biases altering the results. Previous research indicates that
         sentiment analysis tools show gender and race biases, and word embed-
         dings discriminate against women. This research investigates previously
         undefined non-native speaker bias in sentiment analysis, i.e. unintended
         discrimination against English texts written by non-native speakers of
         English. Non-native speakers of English tend to use cognates, English
         words that have origin in the speaker’s language. To measure the non-
         native speaker bias in 4 lexicon-based sentiment analysis systems, a new
         Cognate Equity Evaluation Corpus was created, based on previous work
         in the literature for measuring racial and gender biases. The tools gave
         significantly different scores to English texts with features of non-native
         speakers. The bias discovered in lexicon-based tools was mitigated by
         updating 4 lexicons for English cognates in 3 languages. This paper pro-
         poses a generalisable framework for measuring and mitigating non-native
         speaker bias.


Keywords: Fairness in Machine Learning, Natural Language Processing, Bias
Mitigation, Non-Native Speaker Bias, Sentiment Analysis


1      Introduction
The number of domains depending on data analysis and machine learning has
been growing with a previously unseen pace. As it happens, the fairness of ma-
chine learning models and their application is becoming increasingly more impor-
tant. There is, however, no single established definition of unintended bias [5].
In this paper, bias is understood as a preference of some attributes over oth-
ers. When this preference is not intentional, the fairness of the model needs to
be questioned [1]. Unfairness in machine learning can lead to consequences of




Copyright © 2019 for this paper by its authors. Use permitted under Creative Commons License
Attribution 4.0 International (CC BY 4.0).
various scales including not hiring a person because of their gender that was
disfavoured during an automated CV screening, or not allowing a prisoner pa-
role because of their skin colour rather than their criminal record and/or recent
reform (ibid.).
    Natural language processing (NLP) is an area of machine learning which in-
cludes various types of analysis of textual data, e.g. text classification, sentiment
analysis, text generation and so on. Just like in machine learning in general, un-
intended biases have been noticed in NLP - e.g. word embeddings which are used
for various tasks ranging from Google news sorting to abusive content filtering
have been found to be biased against women [3]. It has also been found that
sentiment analysis systems which are used both in academia and industry can
discriminate against races and genders [14]. Others have also observed that gen-
der can significantly affect results [7,8,15]. Yet, there are few approaches for the
general study, identification or mitigation of these effects.
    It has been shown that non-native speakers of English tend to use cognates,
i.e. English words that look similar to the words of their native language in
their English texts more often (e.g. French speakers are more likely to use ‘fa-
tigue’ (French/Latin origin, cognate of French ‘fatigué’), and German speakers
are more likely to use ‘weary’ (Proto-Germanic origin, cognate of Frisian ‘wu-
urig’) in the same context because of the etymology of those words [16]). Since
the majority of sentiment analysis systems are trained on native speaker data,
we suggest that sentiment analysis systems can be biased against non-native
speaker texts leading to discrimination against non-native speakers of English.
This paper provides a methodology for measurement and mitigation of this bias.
    To address the issue of unintended biases the following research question was
specified and tackled:
‘To what extent can the expansion of the Equity Evaluation Corpus (EEC) with
cognates enable measuring and, where necessary, mitigating bias in lexicon-based
sentiment analysis systems against English texts written by non-native speakers
(speakers of French, Italian and Spanish)?’
    To address the research question several sentiment analysis (VADER, Sen-
timentR, TextBlob, Afinn) systems were measured and debiased. The specified
research question aims at solving the issues of unintended biases in natural lan-
guage processing, and bringing value to NLP researchers, linguists, and data
analysts who deal with textual data. The results of this research will help prac-
titioners reduce a method bias in the application of NLP methods. This will
especially be the case in the use of online data, for example from Social Media,
online reviews, blogs etc. The sentiment analysis systems specified were chosen
based on their popularity and functionality. The languages are chosen based on
comparatively large number of English cognates they have.
    The rest of the paper is structured as follows: section 2 presents relevant
related work and its influence on this work; section 3 describes the methodology
applied; section 4 summarises the implementation, evaluation and results of our
study; finally, section 5 concludes the paper.
2     Related Work
Fairness in machine learning is a growing concern both in industry and academia.
The scope of the reviewed literature is from 1996 to 2019.

2.1   Fairness and Unintended Bias in Machine Learning
As the reliance on machine learning for decision making grows in various spheres
of business and life, the fairness of those decisions becomes increasingly impor-
tant. To the best of the authors’ knowledge there is no standardised definition
of the concept of fair machine learning, and depending on the domain algo-
rithmic fairness can be understood in a number of ways. It is suggested, that
machine learning algorithms or models have to be biased towards some partic-
ular decision, however, when this bias is unintended, a model or algorithm can
be considered unfair [1].
     The source of bias can be different on a case by case basis, but generally it
is observed that bias comes from the training data [5] - in one example of image
recognition, people with darker skin were proved to be more difficult to identify
than people with fairer skin, because the training dataset was imbalanced and
contained significantly more images of white people [4]. Dataset imbalance is
also observed in NLP, in toxicity (i.e. toxic language) and abuse detection in
particular [15]. Unintended bias can be introduced to the data by personal biases
during manual data labelling [8]. Another source of bias can sometimes be model
architecture [15] - the models that see each word as a separate feature can show
higher rate of false positive scores in abusive content classification.
     Generally, there are 2 types of fairness that provide guidelines for determining
a case-specific approach - individual fairness and counterfactual one. Individual
fairness comes from the classification tasks - it is suggested that two similar
observations or data points should be classified into the same category. Originally
it was achieved using a distance metric that would calculate how similar the
observations are [9]. Counterfactual fairness depends on the concept of adding
counterfactuals for each level of data such as sex or skin colour [13].
     In this paper, individual fairness is assumed to be the guiding type of fairness
- i.e. it is suggested that similar sentences, one written by native speakers and
another written by non-native speakers should get similar results from NLP
systems. However, unlike in [8], in this case it is not connected with classification,
and applies to a sentiment analysis score instead. The following section offers
more details on state-of-the-art bias measurement and mitigation in textual data.

2.2   Biases in Natural Language Processing
Existing Approaches to Measuring Biases in NLP:
   When it comes to NLP, word replacement as a method to determine if bias is
prevalent. To measure the bias against identity terms such as ‘muslim’, ‘gay’, and
others in toxicity classification, [8] have created a synthetic testing dataset which
contained more than 70000 sentences, half of which were toxic and half of which
were not. The dataset was based on several manually created templates such as
‘IDENTITY people are just like everyone else’. Using replacement, identity terms
combined with the templates produced the final dataset used in the publication.
    A similar approach was used for measuring bias against age in sentiment
analysis. Sentences containing explicit (‘old’, ‘young’) or implicit (words that
are likely to be used by old or young people) age encodings were used to test
15 sentiment analysis tools. The sentiment was measured for sentences with the
term originally contained in the sentence, and then with the opposite one [7].
     [14] propose to use Equity Evaluation Corpus3 the creation of which is de-
scribed in detail in that paper. The authors created a corpus of sentences using
templates they suggested for various emotions and for the neutral sentences.
The emotions included anger, fear, joy and sadness, based on the Roget’s The-
saurus. The sentence templates used in this paper were based on these same four
emotions.
    The three examples described above are very useful for our approach, as they
focus on the influence of a particular word like an identity term or an age re-
lated adjective on the outcome of the sentiment analysis results. The focus of
this paper is also word-based - it relies on synsets, or pairs of words, that include
a cognate and its non-cognate synonym.

Mitigation of Unintended Biases in Natural Language Processing:
    It is found, that generally mitigation of biases in sentiment analysis and re-
lated tasks can be performed either through changing an algorithm (in-processing)
or through changing the training data (pre-processing).
    Changing the training data was observed in several papers related to senti-
ment analysis. To mitigate the bias related to age, 2 custom sentiment analysis
tools based on the bag-of-words text classification were built with a logistic re-
gression. Training data used for Sentiment140 4 was modified to suit the needs
of the research - i.e. measure bias against age originating from the training
data. Training data for the dataset was filtered to identify records containing
words related to age like ‘young’, ‘old’ and some others resulting in about 14
000 tweets. As a result it was confirmed that the age bias in sentiment analysis
at least partially derives from the labels in the training data, and as long as the
examples including words related to age are excluded, bias can be significantly
mitigated [7].
    Similarly to the previous example, mitigation of biases can also be done
through an unsupervised balancing of the training dataset [8].
    It is also important to point out that in some cases mitigation of biases is
not attempted due to the complexity of the task. [14] measured the bias against
race and gender for 200 sentiment analysis tools, however they concluded that
removing the bias is better left for the future work.

3
  https://saifmohammad.com/WebPages/Biases-SA.html, source of the data, accessed
  on the 17th of July, 2019.
4
  http://www.sentiment140.com/, accessed on the 22nd of July, 2019.
2.3   Existing Problems in NLP Connected to Non-Standard English
Since the main focus of this paper is on English texts produced by non-native
speakers, it is important to understand how different this type of English texts
can be and how strongly it influences the outcomes of various NLP tasks.
    The term non-standard English can be applied to all the non-standard di-
alects and variants of English spoken by non-native speakers, and also to the
non-standard Englishes spoken by native speakers such as Cockney accent or
Scottish accent. Each non-native speaker might use a slightly different version
of English depending on their native language and level of proficiency in En-
glish [17].
    One of the features of non-native Englishes includes using cognates - English
words that have a similarly looking or sounding word in the speaker’s native
language. It was observed that even speakers with high level of English profi-
ciency tend to prefer cognates over other words if a cognate exists. The presence
of a cognate word in a piece of text can be enough to identify a speaker’s native
language. Examples of such words include a pair ‘weariness’ (German origin)
- ‘fatigue’ (French origin) - a German speaker is more likely to use the first
word, whereas a French speaker is likely to choose the second one because of
the etymology of the words ( [16]). This observation is the basis of the project’s
hypothesis - since speakers of different languages use different cognates in the
same situations, their texts might get different sentiment analysis results where
no difference was intended.
    Non-standard English includes not only different vocabulary choices, but also
different pronunciation. Various accents of English introduce a great variety of
sounds for the same letter combinations. This can lead to issues in automated
speech recognition (ASR) [17], and to transfer of pronunciation into spelling [2].
    Consideration of these and other specifics of non-standard English is essen-
tial for NLP tasks, due to the fact that English is the primary communication
language in many online communities and geographical locations regardless of
the native language of the speakers.

3     Methods
Both components of the adopted scientific methodology - measurement and mit-
igation of biases - are implemented following a modified KDD approach [10].
Figure 1 presents the 6 phases which were followed during the implementation.
Unlike the traditional KDD approach, it included the phase of additional data
creation i.e. a dataset for measuring the bias that was compiled using the avail-
able word pairs and sentence patterns. Another addition is the last phase of bias
mitigation that is normally not a part of a KDD method.

3.1   Data
For the implementation of this work, 5 data sources were used, 4 of which are
open source, and one created by the authors. To process these data, 4 sentiment
analysis lexicons (VADER, SentimentR, TextBlob, Afinn) were used.
    Fig. 1. Sentiment Analysis Bias Measurement and Mitigation Methodology



Etymological WordNet: Etymological WordNet [6] is a collection of etymo-
logical origins of more than 500 000 words and more than 6 million links. The
information for the dataset was collected from Wiktionary in 2013 and made
available in 2014. The choice was motivated by related work presented in section
2 [16]. In total the dataset contains 3 columns of 6 000 000 rows.
WordNet:WordNet [11] (also available as a package in Python) is similar to
a thesaurus - a collection of synonyms, antonyms, and other word groups. Its
functionality is used to collect synsets - sets of synonyms - for English words
that have a specific origin.
Reddit L2 Dataset: Reddit L2 Dataset [16] is a collection of Reddit posts in
English written by French speakers, and was used to find French cognates that
are in use. Nearly 90 000 posts were scanned for the cognates. Cognate lists of
other languages did not require this step due to low numbers that could bias the
results of statistical testing.
Equity Evaluation Corpus: Equity Evaluation Corpus is a dataset created
by [14] to measure the bias against gender and race in sentiment analysis. The
corpus has 8640 sentences created using 40 emotion words and 11 sentence pat-
terns.
Creation of The Bias Measurement Dataset The Cognate Equity Eval-
uation Corpus (CEEC) is based on the Equity Evaluation Corpus (EEC) [14]
created to measure gender and racial biases.
     To provide a reliable corpus for non-native speaker bias measurement, a sen-
tence template, EEC emotion words and cognate pair words were used.
     The template used is ‘Talking about OBJECT made me feel EMOTION
WORD.’. This template is based on the template from EEC ‘PERSON SUB-
JECT made me feel EMOTION WORD.’ There are several reasons behind not
introducing more sentence templates. First is that sentence templates require suf-
ficient time to be verified, as there are multiple methodologies behind creating
them, and thus left for future work. Second is that the purpose of the corpus is to
provide NLP researchers with an efficient way of detecting non-native speaker
biases. Assigning sentiment takes different amount of time depending on the
sentiment tool and the amount of text. Since the number of word pairs is much
higher than in EEC, it was decided that one template with 4 emotions and 40
emotion words would be sufficient at this stage.
    In every sentence the OBJECT was replaced with one of the words from
each cognate pair. To get a cognate pair, all the English words with origin in the
target language were selected from the Etymological Wordnet. Then each word
was assigned a synset (synonym set) using the WordNet package in Python.
Every word had a different number of synonyms, ordered by how often they are
used. Only the most commonly used synset was kept for each word to scope the
study and ensure balance in the dataset. Only noun pairs were kept for 2 reasons:
1) every part of speech would require a different template, so it was decided to
keep only one due to the time limits; 2) nouns were the most represented part
of speech. Different numbers of pairs for each origin language correspond to the
nature of etymology of English words.
    The emotion words for the template were retrieved from the EEC. In total
4 emotions were present in EEC - anger, fear, joy, sadness. Each emotion was
represented by 10 words, e.g. ‘angry’, ‘frustrated’, ‘serious’, ‘enraged’, ‘excited’,
‘relieved’.
    In total 3 versions of CEEC were created, as can be seen in Table 1.

                    Table 1. Cognate Equity Evaluation Corpus

        Language Cognate Pairs Emotion Words Total Number of Sentences
         French      292            40                23360
         Spanish      32            40                 2560
         Italian      45            40                 3600




3.2   Feature Selection
The features required for this work are the “level” of the sentiment analysis and
the text that will be used. When it comes to the level, sentence is chosen as a
lot of textual data is being created online in microblog environments such as
Twitter or Facebook, and the texts of this kind are usually short and do not
always include more than 2-3 sentences. Another reason is the field standard -
as was observed in the literature, most papers focus on sentences.
    Sentiment analysis results may differ depending on capitalisation, punctu-
ation marks, word choice, contrasting conjunctions (e.g. ‘but’), negators (e.g.
‘not’), degree modifiers (e.g. ‘very’, ‘slightly’, ‘a lot’) [12]. Since the focus of the
paper is to identify and mitigate discrimination against non-native speaker texts
that include cognates, we focus only on one feature: word choice, and examine
its influence on the outcome (i.e. observed sentiment).
    Languages of word origin chosen for this paper are French, Spanish and
Italian. The choice is motivated by a high number of cognates in these languages
due to etymological links between English and these languages.
3.3   Sentiment Analysis Systems Used
The work described in this paper relies on freely available sentiment analysis
tools that can be seen in Table 2. To be chosen for the work, the tool had to
satisfy the following requirements: it has to be completely free or have a free trial
version; it has to be available for English language texts; it has to be available
whether in R or Python, the languages commonly used by data scientists and
NLP researchers; the sentiment value assigned to sentences has to be numeric
and not categorical (e.g. ‘good’, ‘bad’, ‘neutral’). While the selected tools are
not the only ones that satisfy these requirements, they are all used in a variety
of settings (e.g. teaching and research) and diverse enough to afford some degree
of variability in the results.


                    Table 2. Sentiment Analysis Systems Used

                          System         Lexicon Size
                          VADER [12]     7517
                          Afinn5         3382
                          TextBlob6      2930
                          SentimentR7    11710




3.4   Measuring Bias in 4 Lexicon Based Sentiment Analysis Tools
To measure bias the CEEC dataset created for this work was used. Sentiment
score was assigned to all the sentences using the 4 sentiment analysis tools -
VADER, Afinn, and TextBlob in Python, and SentimentR in R. The sentiment
scores from all tools were merged into one dataset, and the differences were
calculated for a more detailed overview.
    Assignment of the sentiment was performed using special commands available
in the libraries. The standard settings were used for all the tools to achieve the
score that is embedded in the lexicons of each tool.


4     Evaluation and Results
4.1   Evaluation and Results before Bias Mitigation
To evaluate the results, a Wilcoxon signed rank test was performed for each
emotion. For each origin language and for each emotion the group of sentences
containing the cognate words was compared to the group of sentences with no
cognate word. Where the difference was significant at p-value less than 0.05,
the presence of bias was confirmed. For each sentiment system the results were
different. The scores were recorded in tables for each of the cognate origin lan-
guage - French (Table 3), Spanish (Table 4), and Italian. Only the first two are
presented as there was no significant bias observed against Italian cognates. Sen-
timentR shows bias against the biggest number of French cognates - 133 out of
292. TextBlob shows bias against the least number of cognates - 19 for polarity
and 20 for subjectivity. Essentially this means, that when a French person uses
a cognate, e.g. ‘deficit’ which has a French etymology instead of ‘shortage’, the
resulting sentence is likely to receive a more extreme sentiment score. It can be
seen that the bias against cognates is present in sentences with various emotions
in almost all sentiment tools. When it comes to Spanish cognates, SentimentR
also shows bias against the biggest number of cognates - 6 out of 32. V=0 indi-
cates that the scores for sentences with cognates and sentences without cognates
were identical and as a consequence no bias was observed, as in the case of
TextBlob. The scores were checked to ensure this. Measurement of bias against
Italian cognates showed no significant bias due to the fact that none of the words
in the pairs is present in any of the default lexicons.


Table 3. Results of Significance Test-       Table 4. Results of Significance Test-
ing for French Cognates                      ing for Spanish Cognates

   Tool       Emotion SignDiff P value           Tool       Emotion SignDiff P value
1 Vader       anger   yes      0.01541        1 Vader       anger   no       0.06409
2 Tblob Pol anger     yes      0.004203       2 Tblob Pol anger     no       V=0
3 Tblob Subj anger    no       0.2802         3 Tblob Subj anger    no       V=0
4 Afinn       anger   yes      0.01114        4 Afinn       anger   yes      0.001904
5 SentR       anger   yes      8.448e-06      5 SentR       anger   yes      0.0245
6 Vader       fear    yes      0.009291       6 Vader       fear    no       0.06451
7 Tblob Pol fear      yes      0.0001365      7 Tblob Pol fear      no       V=0
8 Tblob Subj fear     no       0.7473         8 Tblob Subj fear     no       V=0
9 Afinn       fear    yes      0.01114        9 Afinn       fear    yes      0.001904
10 SentR      fear    yes      5.645e-06      10 SentR      fear    yes      0.0245
11 Vader      joy     no       0.5923         11 Vader      joy     no       0.06456
12 Tblob Pol joy      yes      1.815e-05      12 Tblob Pol joy      no       V=0
13 Tblob Subj joy     yes      0.02074        13 Tblob Subj joy     no       V=0
14 Afinn      joy     yes      0.01114        14 Afinn      joy     yes      0.001904
15 SentR      joy     yes      0.03043        15 SentR      joy     yes      0.02469
16 Vader      sadness yes      0.01857        16 Vader      sadness no       0.06458
17 Tblob Pol sadness yes       0.002438       17 Tblob Pol sadness no        V=0
18 Tblob Subj sadness no       0.2796         18 Tblob Subj sadness no       V=0
19 Afinn      sadness yes      0.01114        19 Afinn      sadness yes      0.001904
20 SentR      sadness yes      8.419e-06      20 SentR      sadness yes      0.02452




    Mitigating the Bias: To mitigate the bias against texts written by non-
native speakers of English, the steps described below were taken. Due to com-
paratively smaller sample of sentences representing positive emotions (negative
to positive sentences ratio is 3:1) only debiasing tools for negative emotions was
added as objective of the research, to ensure fair and generalisable results.
    First, the results of the bias measurement were observed for every sentiment
system, and the word pairs with difference in scores were organised into lists.
The lists were updated in the following way - cognates that had different score
in the lexicon were changed to have the same score as the non-cognate word,
and the cognates that were not in the lexicons were added with the score equal
to the non-cognate word from the pair. This was done by assigning the scores
to the words, and then adding the resulting cognate lists.
    For Vader there is a special command that was used to update the lexicon
by adding the words with their scores.
    For Afinn no such command was found. To update the lexicon, the TXT file
was found in the Python directory, and amended according to the bias. This file
then can be used instead of the original lexicon, by either using a special set of
commands, or by replacing the original file with the updated lexicon.
    TextBlob debiasing is similar to Afinn in terms of manually updating the
lexicon file in the Python directory. The file has to have the same name as
the original lexicon. In the case of different lists for different languages it can
create some inconvenience, however, renaming files is not time consuming and
guarantees that the approach will work.
    SentimentR allows adding any lexicon to the system. To debias the tool, the
original lexicon was amended to reflect the correct scores for the cognates and
saved as a new lexicon key. Unlike all the other tools, SentimentR allows to have
various lexicons at the same time - i.e. lexicons debiased for French, and Italian
cognates can exist as separate files simultaneously.


4.2   Evaluation and Results after Bias Mitigation

To determine the effectiveness of the debiasing process, the second round of
significance testing was performed. The results show that after debiasing, the
sentences with Spanish cognates and sentences without them receive identical
scores in all 4 sentiment analysis systems for not only 3 negative emotions, but
also the positive one (joy).
    As for the French cognates, it was possible to debias all sentiment tools for
all negative emotions - sadness, anger, and fear.
    The test results show that SentimentR and TextBlob still show bias against
cognates in sentences with positive emotion words related to joy. Debiasing tools
for positive emotions is not in the objectives of this research, however, some
insights given below were discovered.
    After analysing the pairs with differences in scores it was concluded that in
case of SentimentR the bias remained where synonyms consisted of 2 words, e.g.
for French cognate ‘boutique’ the paired synonym is ‘dress shop’. SentimentR
is structured in such a way that phrases like this get broken down and receive
different scores. In the case of TextBlob, the reason behind the remaining bias is
that the lexicon has different scores for various meanings of the affected words.
To debias further, additional filtering and more data are necessary. It is also
identified, that due to the fact that emotion words related to negative emotions
such as anger, fear, and sadness are more extreme in scores, the bias for them
was mitigated without additional filtering or data.
    The approach implemented in this paper can be further generalised
and used to debias sentiment analysis systems for cognates not only in English
but other languages as well, as can be seen in Figure 2. It was successfully
performed for 4 emotions in 4 tools for Spanish cognates, and for 3 emotions in
4 tools for French cognates.




        Fig. 2. Generalisable Bias Measurement and Mitigation Framework




5   Conclusion

In this paper, we have illustrated that texts with non-native speakers charac-
teristics are likely to be handled quite differently by sentiment analysis tools.
To show this, we expanded the Equity Evaluation Corpus (EEC) to enable the
measurement of bias against English texts written by speakers of French, Italian,
and Spanish in lexicon-based analysis systems (VADER, SentimentR, TextBlob,
Afinn) for 4 emotions. We then demonstrated how to mitigate this bias against
speakers of Spanish and French in 4 sentiment systems for 3 emotions. No bias
was detected against speakers of Italian, so no mitigation was required.
    This work can be extended in a number of ways. Increasing the number
of languages observed and the number of sentence patterns used would permit
a more expansive discussion of non-native speaker bias. It would be useful to
also observe the bias against more emotions, especially positive ones. We have
studied dictionary-based tools, as such corpus based merit study too, but would
require extensions to be methodology developed here as it would involve building
machine learning models to facilitate sentiment analysis of texts.
    The results of this research contribute to fairness in machine learning lit-
erature, ensuring that non-native speakers of English face less discrimination
in research designs. The findings of this work can enable data analysts and re-
searchers improve the way textual data is analysed to avoid unintended bias
against English texts produced by non-native speakers at a bigger scale.


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