1. Role of NLP in Linguistics 16-07-2010 Dipti Misra Sharma Language Technologies Research Centre International Institute of Information Technology Hyderabad India

2. NLP and Linguistics Have similar goals – Understanding human language(s) NLP relies on the theoretical models provided by linguistics – Therefore, NLP definitely needs linguistics By the way, The concept of ‘zero’ in Indian mathematics originated in Indian grammatical theory* *Euclid and Panini by J.F. Stall – Philosophy East and West 1965‏

3. NLP helps in some linguistic tasks NLP tools can be useful for certain linguistic tasks such as collecting, organizing, classifying data, providing statistics etc. This saves efforts, brings forth facts which help in generalizations Makes life easier for linguists

4. NLP techniques can be useful for creating linguistic resources such as verb frames, transfer grammars, bilingual lexicons etc Studies in CL have also shown the usefulness of NLP techniques in historical linguistics (e.g. phylogenetic trees) NLP and Linguistics

5. What else ? NLP researchers and linguists are looking at language from different perspectives Resource creation for NLP involves a close study of large scale real time data (e.g. linguistic annotation) This can raise issues which have theoretical implications

6. Our experience There is a long list of Hindi lexical items which are historically derived from Sanskrit verb roots but are categorised as adjectives in Hindi Exp ‘sthita’ (situated), swiikrita (accepted), sviikaarya (acceptable), likhita (written) …… However, these ‘adjectives’ of Hindi have modifiers which are more like arguments dillii mein sthit qutub miinaar ek darshaniiy sthal hai. Delhi in situated Qutub Minar one worth-watching place is unke dvaaraa kathit kahaaniyaan bahut pracalit hain Them by told stories very popular are

7. The issue Both ‘dillii mein’ and ‘unke dvaaraa’ have appropriate case markers ‘mein’ is locative and ‘dvaaraa’ agentive These adjectives are historically non-finite verbs but Hindi grammars do not account for them so anymore The morphological decomposition of sthita and kathit would lead to a Sanskrit analysis and NOT a Hindi analysis Hindi for example does not have ‘sthaa’ or ‘kath’ as verb roots. It doesn’t have ‘ita’ as an active participial suffix either. So, how do we account for the argument like properties of their modifiers ?

8. Another example Indian languages show frequent use of complex predicates The problem, When is an NV sequence a complex predicate and when it is not ? This is a question which has long being discussed in linguistics literature A set of diagnostics have also been proposed However, Several NV sequences are semantically a single unit but syntactically they fail the diagnostics So, do we consider them as ‘complex verbs’ or as ‘verb arg’ instances ?

9. Conclusions NLP tools and techniques can be useful for linguists The linguistic resource creation for NLP research and applications can also bring up issues which pose interesting linguistic problems