=Paper= {{Paper |id=Vol-2481/paper28 |storemode=property |title=Towards an Italian Learner Treebank in Universal Dependencies |pdfUrl=https://ceur-ws.org/Vol-2481/paper28.pdf |volume=Vol-2481 |authors=Elisa Di Nuovo,Cristina Bosco,Alessandro Mazzei,Manuela Sanguinetti |dblpUrl=https://dblp.org/rec/conf/clic-it/NuovoBMS19 }} ==Towards an Italian Learner Treebank in Universal Dependencies== https://ceur-ws.org/Vol-2481/paper28.pdf
       Towards an Italian Learner Treebank in Universal Dependencies
                  Elisa Di Nuovo                        Cristina Bosco
         Dipartimento di Lingue e Letterature        Alessandro Mazzei
            Straniere e Culture Moderne             Manuela Sanguinetti
                 University of Turin              Dipartimento di Informatica
          elisa.dinuovo@unito.it                      University of Turin
                                          {bosco,mazzei,msanguin}@di.unito.it


                      Abstract                             and Paquot, 2015; Malmasi, 2016), Grammatical-
                                                           Error Detection and Correction (Leacock et al.,
    In this paper we describe the preliminary              2015; Ng et al., 2014), and Automated Essay Scor-
    work on a novel treebank which includes                ing (Higgins et al., 2015).
    texts written by learners of Italian drawn                In this paper we describe the development of a
    from the VALICO corpus. Data pro-                      novel learner Italian treebank, i.e. VALICO-UD,
    cessing mostly involved the application of             in which Universal Dependencies (UD) formal-
    Universal Dependencies formalism and er-               ism is tied to error annotation. The considerations
    ror annotation. First, we parsed the texts             of the annotation process, carried out on a set of
    on UDPipe trained on the existent Ital-                one hundred sentences selected from a subcorpus
    ian UD treebanks, then we manually cor-                of VALICO1 (see Table 1) (Corino and Marello,
    rected them. The particular focus of this              2017), allowed us to test a pilot scheme which pin-
    paper is on a one-hundred-sentence sam-                points some of the features of L2 Italian.
    ple of the collection, used as a case study               This paper is organized as follows: in Section 2
    to define an annotation scheme for identi-             we provide an overview of LC, focusing on Ital-
    fying the linguistic phenomena character-              ian resources in particular; in Section 3 we present
    izing learners’ interlanguage.                         the data and the error annotation of VALICO-UD;
                                                           in Section 4 we offer some examples of how we
1   Introduction                                           applied literal annotation to the learner sentences
                                                           (LS) and, finally, in Section 6 we present conclu-
The increasing interest in Learner Corpora (hence-         sion and future work.
forth LC) is twofold motivated. On the one hand,
LC are an especially valuable source of knowl-             2       Related work
edge for interlanguage varieties. They allow in-
depth comparisons of non-native varieties, help-           LC, also called interlanguage or L2 corpora, are
ing to elucidate the properties of the interlan-           collections of data produced by foreign or sec-
guage developed by learners with different mother          ond language learners (Granger, 2008). Most LC
tongues and learning levels. For this reason, LC           projects were launched in the nineties and focused
are important resources enabling data-driven stud-         mainly on learner English (Tono, 2003), but re-
ies exploited within several research areas, such          cently we have witnessed an increasing interest
as Second Language Acquisition, Foreign Lan-               in LC for other target languages. This has con-
guage Teaching, Contrastive Interlanguage Anal-            tributed to the establishment of learner corpus re-
ysis, Computer-aided Error Analysis, Computer-             search (Tono, 2003).
Assisted Language Learning and L2 Lexicogra-                  LC can be enriched with Part of Speech (PoS)
phy (e.g. (Pravec, 2002; Granger, 2008; McEnery            tagging, syntactic, semantic, discourse structure
and Xiao, 2011)). On the other hand, LC have               and error-tagging (with explicit or implicit target
raised considerable computational interest, which          hypotheses2 ) annotation (Garside et al., 1997). To
is closely related to their usefulness in tasks            provide linguistic annotation, NLP tools are of-
such as Native Language Identification (Jarvis             ten used (Huang et al., 2018) and combined with
                                                               1
     Copyright c 2019 for this paper by its authors. Use       http://www.valico.org/
                                                               2
permitted under Creative Commons License Attribution 4.0       A reconstructed LS on which error identification is based
International (CC BY 4.0).                                 (Reznicek et al., 2013).
human post-editing in order to overcome issues                collection of non-native Italian texts elicited by
arising from the failures of the automatic analy-             comic strips proposed to the learners. It consists of
sis (Geertzen et al., 2013; Granger et al., 2009;             a selection of narrative and descriptive texts pro-
Dahlmeier et al., 2013).                                      viding a large variety of structures beyond simple
   Among the 14 learner Italian corpora registered            presentative/existential constructions.
in the Learner Corpora around the World list3 ,                  The portion of VALICO that we selected for the
the majority are in the form of plain texts, or they          treebank is made up of 237 texts (2,261 LS) orga-
only annotate PoS (COLI, LOCCLI and CAIL24 ,                  nized in four sections as shown in Table 1.
and VALICO), while only MERLIN (Boyd et al.,
2014) annotates syntax and errors (with explicit                         L1           # Texts    # LS Tokens
target hypotheses).                                               English (EN)          60          8,285
   Although MERLIN contains 816 texts written                     French (FR)           59          7,301
in non-native Italian (Boyd et al., 2014), they are               German (DE)           58          7,417
not balanced for learners’ mother tongue and are                  Spanish (ES)          60          7,365
not annotated using a standard annotation for syn-
                                                                 EN+FR+DE+ES            237         30,368
tax, which would allow comparisons with other re-
sources. To fill this gap, we decided to develop               Table 1: VALICO-UD in figures – LS section.
VALICO-UD, a L1-balanced resource developed
within the UD formalism, thus providing a greater
potential for contrastive analysis. Indeed, a UD-                Although the unpredictability and variation of
annotated LC can be compared with other LC                    a learner product, in terms of vocabulary, mor-
(therefore different interlanguages) or also with             phology and syntax, makes parsing a LC an espe-
native corpora of the L1 involved. For all these              cially challenging task (Corino and Russo, 2016;
reasons, we decided to develop this new learner               Dı́az-Negrillo et al., 2010), it is highly recom-
Italian treebank within the UD formalism. Refer-              mendable for smoothly retrieving interlanguage
ences were the English and Chinese experiences,               features. Due to this peculiarity of interlanguage,
respectively the English Second Language (ESL)                keeping separated the LS from its specifically built
(Berzak et al., 2016) and the Chinese Foreign Lan-            target hypothesis (TH) is highly recommended
guage (CFL) (Lee et al., 2017) treebanks.                     (Lüdeling et al., 2005).
   The scholars involved in the annotation of the                Our annotation scheme for learner Italian uses
ESL and CFL treebanks decided to follow a well-               the inventory of the Italian UD PoS tags and de-
established line of work, for which learner lan-              pendency relations (Bosco et al., 2013; Bosco et
guage analysis is centered upon morpho-syntactic              al., 2014) and the related guidelines. In addition,
surface evidence. This is motivated by various                we tried to follow as much as possible the ESL
studies, e.g. (Dı́az-Negrillo et al., 2010; Ragheb            treebank to have comparable resources.
and Dickinson, 2012), in which the difference                    First, we trained UDPipe (Straka et al., 2016)
between morphological and distributional PoS is               on the Italian UD corpora, which include stan-
stressed. We decided to follow this line of research          dard texts, ISDT (Bosco et al., 2014), and Twitter
annotating discrepancies between morphological                posts, POSTWITA-UD (Sanguinetti et al., 2018).
and distributional PoS, as described in the next              Second, we automatically parsed VALICO-UD.
sections. However, in lieu of carrying out manual             Third, we manually corrected the treebank. This
annotation from scratch, such as in the ESL, we               step is currently ongoing and we envision the tree-
combined automatic annotation and manual post-                bank to be released in the UD repository in a few
editing (as shown in the next section).                       months.
                                                                 For each sentence in VALICO-UD we provide
3   Data and annotation                                       two distinct versions both annotated in UD and
The data of VALICO-UD are drawn from the                      tied to an error encoding system (see Section 3.1):
VALICO corpus (Corino and Marello, 2017), a                   one version for the LS and the other for its TH.
                                                              The latter will differ from the former only when
    3
      https://uclouvain.be/en/research-                       some errors occur. As a trial for this scheme, we
institutes/ilc/cecl/learner-corpora-around-the-world.html.
    4
      COLI, LOCCLI and CAIL2 are developed at Università     selected one hundred sentences (i.e. sample set)
per Stranieri di Perugia and coordinated by Stefania Spina.   containing each at least one error to be annotated.
 # sent id = NameSurname00135LS                                                  # sent id = NameSurname00135TH
 # text = Può essere un rubadore perche ha la cara chiusa e minacciata.         # text = Può essere un rubatore perché ha la faccia chiusa e minacciosa.
 # err = Può essere un hRNihiirubadoreh/iihcirubatoreh/cih/RNi                  # err = Può essere un hRNihiirubadoreh/iihcirubatoreh/cih/RNi
 hMIihiipercheh/iihciperchéh/cih/MIi ha la hFNLihiicarah/ii                     hMIihiipercheh/iihciperchéh/cih/MIi ha la hFNLihiicarah/ii
 hcifacciah/cih/FNLi          chiusa      e        hDJihiiminacciatah/ii         hcifacciah/cih/FNLi           chiusa       e       hDJihiiminacciatah/ii
 hciminacciosah/cih/DJi.                                                         hciminacciosah/cih/DJi.
 # segment =                                                                     # segment =
 # typo = 8 ADJ, 11 VERB                                                         # typo = 8 ADJ, 11 VERB
 # foreign = 8 NOUN                                                              # foreign = 8 NOUN
 # context = 4 NOUN                                                              # context = 4 NOUN
 1      Può            potere         AUX          VM           4       aux     1      Può             potere          AUX           VM           4     aux
 2      essere          essere         AUX          V            4       cop     2      essere           essere          AUX           V            4     cop
 3      un              uno            DET          RI           4       det     3      un               uno             DET           RI           4     det
 4      rubadore        rubadore       NOUN         S            0       root    4      rubatore         rubatore        NOUN          S            0     root
 5      perche          perché        SCONJ        CS           6       mark    5      perché          perché         SCONJ         CS           6     mark
 6      ha              avere          VERB         V            4       advcl   6      ha               avere           VERB          V            4     advcl
 7      la              il             DET          RD           8       det     7      la               il              DET           RD           8     det
 8      cara            caro           NOUN         S            6       obj     8      faccia           faccia          NOUN          S            6     obj
 9      chiusa          chiuso         ADJ          A            8       amod    9      chiusa           chiuso          ADJ           A            8     amod
 10     e               e              CCONJ        CC           11      cc      10     e                e               CCONJ         CC           11    cc
 11     minacciata      minacciato     ADJ          A            9       conj    11     minacciosa       minaccioso      ADJ           A            9     conj
 12     .               .              PUNCT        FS           4       punct   12     .                .               PUNCT         FS           4     punct


Figure 1: Example of two CoNLL-U trees of the LS (left) and TH (right) number #35: He-can to-be a
thief because he-has the face closed and threaten PP.


3.1    Error Annotation                                                          sents the general type of error (e.g. wrong form,
In writing the TH we decided to adhere as much as                                omission), while the second letter identifies the
possible to the LS and to focus on linguistic cor-                               word class of the required word”.
rectness (e.g. grammaticality) rather than linguis-                                 To provide a finer-grained description of errors,
tic appropriateness (e.g. register) (Reznicek et al.,                            we used a large variety of letters in the first and
2013)5 . For this reason, sometimes we sacrificed                                second position (e.g. I: inflection, X: auxiliary)
naturalness for the sake of adherence to the LS.                                 and a third letter which encodes information about
This principle was applied also to lexical errors re-                            some grammatical features (e.g. T: tense, M:
quiring replacement. For instance, in Figure 1, the                              mood, G: gender) (Simone, 2008, pp. 303–346)
term “rubadore” in the LS was replaced with “ru-                                 and other phenomena involved (e.g. capitaliza-
batore” and not with its more common synonym                                     tion, language transfer and government). Finally,
“ladro”, thief.6 With this principle in mind, we de-                             Nicholls included a catch-all code (CE: complex
cided to correct words if they are not present nei-                              error) to cover complex, multiple errors. In our
ther in the VINCA corpus7 (the reference corpus                                  sample set, we did not use it because we managed
specifically compiled for VALICO and containing                                  to describe all errors encountered using nested
texts based on the same comic strips but written by                              XML tags. However, we do not exclude that, ap-
Italian native speakers) nor in our reference dictio-                            plying the error codes to the whole corpus, we
nary, Il Nuovo Vocabolario di Base della Lingua                                  might find particularly complex errors which need
Italiana (De Mauro, 2016). In fact, the VINCA                                    to be marked using this code.
corpus is quite small and the language used sounds                               Figure 1 shows an annotation example of a LS
quite unnatural though being produced by speak-                                  along with its corresponding TH in the typical
ers whose mother tongue is namely Italian (see                                   CoNLL-U format and with the resource-specific
Corino and Marello (2017, p. 12)).                                               fields used to encode the error information. The
   Once the target hypotheses are written, we ap-                                sent id field contains the identification code of
plied to them a coding system based on Nicholls                                  the sentence: in the example, NameSurname001
(2003), which was used also in the NUCLE                                         (anonymized here) indicates the unique identifier
(Dahlmeier et al., 2013) and FCE (Yannakoudakis                                  of the text and refers to the transcribers name and
et al., 2011) corpora.        Our system follows                                 surname; the following two-digit number, 35 in
Nicholls’s same principle: “the first letter repre-                              the example, indicates the position of the sentence
   5
      In the future we plan to provide a second TH, focusing                     in the text; finally, LS or TH indicates learner sen-
on linguistic appropriateness.                                                   tence and target hypothesis, respectively. The text
    6
      Although “rubadore” is reported and marked as obsolete                     field contains the uncoded sentence (which can be
in the Italian Dictionary Olivetti, “rubatore” is the variant re-
ported in De Mauro (2016), our reference dictionary.                             the learner sentence or the target hypothesis). The
    7
      http://www.valico.org/vinca.html                                           err field contains the error annotation based on
                                                   Figure 2: LS #10.




                                      Figure 3: Error-annotated sentence #10.


the coding scheme introduced above. The foreign                German word adapted to Italian and meaning lug-
field includes the index and the PoS of the words              gages); thus, we have a cascade hIDG#i h/IDG#i
which are considered errors due to language trans-             tag which embeds a hFNLi h/FNLi tag (Form
fer. The context field contains the index and the              Noun Language transfer).         The next three
PoS of the words which need replacement due to                 tags, hMARi h/MARi, hSARi h/SARi and
wrong context-bound lexical choices8 . Finally, in             hSVi h/SVi, indicate Missing pronoun (A) Rel-
line with the ESL, we used the segment field when              ative (“che”, that), Spelling pronoun Relative
a sentence was wrongly divided and the typo field              (“ce” instead of “che”) and Spelling Verb errors
to indicate PoS distributional-morphological dis-              (“qurda” instead of “guarda”, look), respectively.
crepancies.                                                    There is, finally, another example of nested tag
   In the error-annotated sentence (the “err” field            involving an Inflection Determiner Gender and an
mentioned above), we report the wrong form(s)                  Unneccessary preposiTion errors; this has been
inside the hii h/ii tag and the corrected form(s)              used to indicate the multiple-step shift from the
inside the hci h/ci tag. Figure 3 shows three ex-              LS “sulle” (on the Fem Pl) to its TH counterpart
amples of nested tag and two examples of cascade               “i” (the Masc Pl): the shift involved a change
errors (i.e. an error which is due to the correction           in the gender of the article (from feminine to
of another token) (Andorno and Rastelli, 2009,                 masculine) and the drop of the preposition “su”
p. 52). The hMAXi h/MAXi tag at the beginning                  (on), mistakenly used in the LS.
of the sentence, for example, indicates a missing                 In order to ensure consistency across different
existential-construction pronoun, i.e. “Sono”                  annotators, the error annotation guidelines pro-
(are) instead of “Ci sono” (there are). After                  vide a hierarchical order to be applied when deal-
the insertion of the missing pronoun “Ci”, the                 ing with nested tags. We organized the errors
capital “S” in “Sono” needs to be changed into                 in a pyramid with at the bottom mechanical er-
a lowercase “s”: this is a case in which we have               rors (i.e. tokenization, capitalization, spelling and
a cascade capitalization error and we mark it                  punctuation) and, proceeding towards the apex,
adding a hashtag after the normal error code, as               morphological (derivation and inflection), lexical
in hSVS#i h/SVS#i. Another cascade error is                    (form and replace), and syntactic (missing, un-
found in the next nested tag: we have an Inflection            necessary and word order) errors. For example,
Determiner Gender error which is caused by                     following this hierarchical order, mechanical er-
the correction of the expression “tanti cofferi”,              rors should be corrected before a syntactic error.
involving a determiner and a noun (“cofferi” is a              However, cascade errors make an exception and
   8
                                                               change the correction order, as we seen in Figure
     Only those choices in which there is no mismatch be-
tween distributional and morphological PoS are registered in   3 in which we have a cascade capitalization error
this field.                                                    (SVS#) caused by a missing pronoun error (MAX)
                                             Figure 4: LS #88.




                                             Figure 5: TH #88.


and a cascade inflection error (IDG#) due to a lex-     much as possible to the literal reading of the
ical error (FNL).                                       learner sentence, thereby creating a treebank in
   In the LS sample set, containing 1,860 tokens,       line with the two existing learner treebanks in the
we marked 496 errors (which represent 26,66% of         UD framework (ESL and CFL).
the LS sample set tokens) distributed as shown in       Argument Structure: When some extraneous or
Table 2.                                                unnecessary prepositions occur, we annotate the
                                                        dependencies accordingly. Figure 2 shows a LS in
    Error category        Tag    # occ     % tot
                                                        which the verb “guardare”, look, is used as an in-
    Derivation             D        24    4.84%         transitive verb, thus we annotate its direct object
    Form                   F        71   14.31%         as an oblique9 .
    Inflection             I        72   14.51%         Missing or Unnecessary Words: We annotate
    Spelling               S        92   18.55%         literally when there are missing or unnecessary
    Word segmentation      T        16    3.22%         words. In the example in Figure 2 the clitic pro-
    Word order             W        15    3.02%         noun “ci” is missing , thus we treated “sono” as a
    Missing word           M        76   15.32%         copular verb. There are other cases in which the
    Unnecessary word       U        55   11.09%         clitic pronoun “ci” is mistakenly combined with
    Replace word           R        75   15.12%         the verb to be forming an existential clause, and
                                                        consequently causing a distributional mismatch
    Total                  –       496          –
                                                        (e.g. LS: “[...] non ci era pericoloso o violento”,
Table 2: Error categories as encoded in the first       TH: “[...] non era pericoloso o violento”10 ). In
letter (general error type) and their distribution in   these cases we mark in the “typo” field the mor-
the sample set.                                         phological PoS and in the PoS column the distri-
                                                        butional PoS, cf. Figure 1.
                                                        Extraneous Word Forms: When the learner mis-
4    From VALICO to VALICO-UD                           uses existent word forms, we annotate them lit-
                                                        erally. In Figure 4, the learner used a gerund,
In this Section we describe how we applied literal      “leggendo” (reading), instead of the infinitive “ a
annotation to the (morpho-)syntactic structure of
                                                           9
the LS in particular, relying on the Universal De-            In all the examples SE stands for spelling error, REFL
pendencies scheme.                                      for reflexive pronoun, PP for past participle, GE for gerund
                                                        and Impf for imperfect tense.
Literal Annotation                                         10
                                                              LS: “[...] not there it-be Impf dargerous or violent”, TH:
We annotated UD PoS and relations sticking as           “[...] not it-be Impf dangerous or violent”.
leggere” (to read). We then labeled it as an ad-                      cerning the LS section) both LS and TH sec-
verbial clause in the LS (Figure 4) and as an open                    tions were annotated by two independent anno-
clausal complement in the TH (Figure 5).                              tators. The inter-annotator agreement was then
Exceptions to Literal Annotation                                      computed, considering two measures in partic-
Spelling: Some examples of spelling errors are                        ular: UAS (Unlabeled Attachment Score) and
presented in Figure 2. We lemmatize and PoS-                          LAS (Labeled Attachment Score) for the assign-
tag them referring to their correct versions, sim-                    ment of both parent node and dependency relation,
ilarly to Andorno and Rastelli (2009, p. 58). Thus,                   and the Cohen’s kappa coefficient (Cohen, 1960)
“ce” was treated as “che”, which,11 , and “qurda”                     for dependency relations only (similarly to Lynn
as “guarda” look.                                                     (2016)). UAS and LAS were computed with the
Word Formation: We do not treat literally valid                       script provided in the second CoNLL shared task
words that are contextually implausible. We con-                      on multilingual parsing (Zeman et al., 2018)16 .
sider them differently depending on the PoS of the                    The results are reported in Table 3, and though
intended word: if the intended word has the same                      showing slightly higher results for the TH set,
PoS we signal it in the “context” field (e.g. LS:                     overall they are very close across the sets. Espe-
“[...] salvando una ragazza indefessa”, TH: “[...]                    cially as regards the LS section, this is evidence of
salvando una ragazza indifesa”12 ), if it is different                the guidelines clarity and of the annotators’ con-
in the “typo” field (cf. Figure 1).                                   sistency, even when dealing with non-canonical
Nonexistent Words: In cases in which the learner                      syntactic structures.
wrote a word which does not exist in Italian and
it is arguably a foreign word, we signal it in the                                  set      UAS         LAS        kappa
“foreign” field13 . In the example in Figure 1 the                                  LS     92.11%       88.63%      0.8988
word “cara” (i.e. an adjective translatable into                                    TH     92.47%       88.88%      0.9068
beloved) is arguably a transfer from the Spanish
noun meaning face. In this case we lemmatize it                       Table 3: Agreement results on the sample set of
with the correct lemma of “cara”. In addition, in                     both LS and TH.
the “typo” field we mark the occurring mismatch
between distributional and morphological PoS.
Word Tokenization: If one word is mistakenly                          6        Conclusion and future work
segmented into two, we use the “goeswith” rela-                       In this paper we introduced VALICO-UD and pro-
tion, as germane to UD annotation guidelines14 . If                   posed an annotation scheme suitable for texts of
two words are mistakenly segmented into one, we                       learner Italian encompassing both UD and error
use X as PoS and decide the relation on a case-                       annotation. Our scheme follows the principle of
by-case basis. For example in LS: “[...] butta tutto                  “literal annotation” and takes PoS and dependency
perterra”, TH: “[...] butta tutto per terra”15 we as-                 morphological-distributional mismatches into ac-
signed to “perterra” PoS ‘X’ and dependency rela-                     count. Our error tag set seems adequate to book-
tion ‘obl’.                                                           mark errors, providing also a fine-grained descrip-
                                                                      tion of some of them.
5    Inter-Annotator Agreement                                           There are a number of possible applications for
As stated above, the complete manual revision of                      the monolingual parallel treebank proposed in this
the treebank is still in progress; however, with                      paper. In the near future, we plan to apply the tree
the aim of assessing the annotation quality of this                   edit distance to LS and TH to measure linguistic
preliminary sample set, as well as the quality of                     competence. Recently, the tree edit distance has
the annotation guidelines (especially the ones con-                   been applied to various tasks (Emms, 2008; Tsar-
                                                                      faty et al., 2011; Plank et al., 2015), and a study
   11
      When “ce” is used instead of “c’è”, there is, we treat it as   has formalized the notion of syntactic anisomor-
a single token and mark it as root, in line with what we would        phism (Ponti et al., 2018). We aim to explore a cor-
have done if it were “c’è”.
   12
      LS: “[...] saving a untiring girl”, TH: “[...] saving a vul-    relation between these notions and the linguistic
nerable girl”.                                                        competence to describe the achievements of for-
   13
      The lemma will be its Italian (quasi-)equivalent.               eign language learners.
   14
      https://universaldependencies.org/u/overview/typos.html
   15                                                                     16
      [...] he-throw everything on the ground.                                 http://universaldependencies.org/conll18/evaluation.html
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