1. Tracking Language Development with Learner Corpora Xiaofei Lu CALPER 2010 Summer Workshop July 12, 2010

2. 2 Outline Corpora and learner corpora Graphic Online Language Diagnostic (GOLD)

3. 3 Corpora and learner corpora What is a corpus Types of corpora Corpus design and compilation Corpus annotation Corpus querying and analysis Learner corpora and L2 development Resources

4. 4 What is a corpus? Leech (1992):  an unexciting phenomenon, a helluva lot of text, stored on a computer Sinclair (1991):  a collection of naturally-occurring language text, chosen to characterize a state or a variety of language Sinclair (2004):  a collection of pieces of language text in electronic form, selected according to external criteria to represent, as far as possible, a language or language variety as a source of data for linguistic research

5. 5 Types of corpora General-purpose vs. specialized corpora  The British National Corpus The British National Corpus  Michigan Corpus of Academic Spoken English Michigan Corpus of Academic Spoken English Native vs. learner corpora  International Corpus of Learner English International Corpus of Learner English Monolingual vs. parallel & comparable corpora  The JRC-Acquis Multilingual Parallel Corpus The JRC-Acquis Multilingual Parallel Corpus  The English-Chinese Parallel Concordancer The English-Chinese Parallel Concordancer

6. 6 Types of corpora (cont.) Corpora representing one or diverse varieties  International Corpus of English International Corpus of English Synchronic vs. diachronic corpora Spoken vs. written corpora

7. 7 Corpus design Purpose and type of corpus  Spoken/written; cross-sectional/longitudinal External criteria for content selection  Communicative function of a text  Mode, medium, interaction, domain, topic Representativeness, balance, size, sampling Design of the BNC

8. 8 Corpus design (cont.) Encoding meaningful metadata information  Learner: L1, gender, program level, discipline …  Sample: date, mode, task, genre, rating …  Facilitates contrastive and longitudinal studies MICASE speaker and transcript attributes

9. 9 Corpus annotation Why annotate Levels of corpus annotation Difficulties for corpus annotation Standards and encoding

10. 10 Why annotate For linguistic research  Allow more effective corpus searches Allow more effective corpus searches For natural language processing  Spelling and grammar checking  Machine translation

11. 11 Levels of corpus annotation Sentence and word segmentation Part-of-speech (POS) tagging and lemmatization Syntactic parsing Semantic, pragmatic, and discourse tagging Learner corpora: error annotation Project-specific annotation

12. 12 Difficulties for corpus annotation Ambiguity  I saw a pig with binoculars.  Problems for tagging, parsing, & WSD Unknown words  Identification  POS tagging  Semantic annotation

13. 13 Standards and encoding Useful standards  Separable  Documentation  Linguistically consensual  Compatibility with existing standards Encoding  Simple encoding: present_JJ  XML-style: present

14. 14 Corpus querying and analysis Using windows- or web-based software  Good for processing raw corpora  Word frequency, concordances, lexical bundles, and keyword lists  Examples: AntConc and GOLDAntConcGOLD Using natural language processing tools  Good for processing annotated corpora  Extracting occurrences of grammatical patterns  Examples: Stanford parser and TregexStanford parser and Tregex

15. 15 Resources Books and journals  Hunston (2002): Corpora in Applied Linguistics  McEnery (2006): Corpus-Based Language Studies  International Journal of Corpus Linguistics  Corpus Linguistics and Linguistic Theory  Corpora Websites and mailing lists  Bookmarks for corpus-based linguists Bookmarks for corpus-based linguists  Linguistic data consortium Linguistic data consortium  The corpora list The corpora list  Stanford Natural Language Processing Group Stanford Natural Language Processing Group

16. 16 Learner corpora and L2 development Samples from same students at different times  Did (targeted) language development take place?  Was a particular pedagogical intervention effective? Samples from different students  What areas do students show different levels of development?  What factors affect students’ language development?

17. 17 Graphic Online Language Diagnostic A free online tool for teachers to assess their students’ language development  Developed at CALPER, Penn State, funded by DOE  Project co-directors: Xiaofei Lu and Michael McCarthy Teachers can use GOLD to  Compile, upload, and manage their own corpora  Share corpora with each other  Search and analyze corpora Demonstration

18. 18 Corpus compilation A user can compile a corpus by  Directly compiling and uploading an XML file  Using the easy-to-use guided XML creation interface An uploaded corpus can be easily managed  Documents can be added or deleted  The whole corpus can be deleted  Content and metadata of individual documents can be easily accessed

19. 19 Corpus sharing GOLD facilitates easy data sharing A corpus may be set to be  Private, shared, or public Corpus owner may give other users right to  View, add, edit, or delete corpora Demonstration

20. 20 Basic corpus information Word count  Alphabetic or numeric order  Can be downloaded as a text file Corpus and document statistics  Mean sentence length  Mean word length  Type-token ratio Demonstration

21. 21 Corpus search Select one or more corpora to search Specify key words or phrases  May use the wildcard character, e.g. book* Specify contexts  Size of context window  Context words and their positions Specify metadata conditions

22. 22 Corpus search results Display of search results  Sortable KWIC display of search results  Sortable graphic display of search results Demonstration

23. 23 Lexical bundle/collocation search Procedure  Select one or more corpora to search  Specify search word  Specify contexts  Specify metadata conditions Search results  Sortable list of n-grams found in selected corpora Demonstration

24. 24 Summary of features Difference from other online tools  Can create, share, and search multiple corpora  Can easily search subsets of data  Can work with any language Summary of corpus analysis functions  Word list  Corpus and document statistics: mean sentence length, mean word length, type-token ratio  Corpus search and collocation search

25. 25 Sample questions to ask With data from an individual student, one can either describe or track development in  Patterns of usages of words and phrases – frequency, underuse, overuse, etc.  Lexical and syntactic complexity  Appropriate usage of words and phrases in context  Patterns of usages of lexical bundles

26. 26 Sample questions to ask (cont.) With data from different (groups of) students, one can compare similarities or differences among different (groups of) students in terms of  Patterns of usages of words and phrases – frequency, underuse, overuse, etc.  Lexical and syntactic complexity  Appropriate usage of words and phrases in context  Patterns of usages of lexical bundles

27. 27 Future enhancements Corpora for benchmarking Multilingual natural language processing Suggestions on desirable functions welcome