1. Introduction to Natural Language Processing Heshaam Faili hfaili@mehr.sharif.edu University of Tehran

2. 2 What is Language? Formal Description A Set of Symbols which … Psychological Description A communication tools Empirical Description A set of following items How are you? Are you ok? I am going to.. …

3. 3 What is NLP? Natural Language Processing (NLP) Computers use (analyze, understand, generate) natural language A somewhat applied field Computational Linguistics (CL) Computational aspects of the human language faculty More theoretical

4. 4 Why Study NLP? Human language interesting & challenging NLP offers insights into language Language is the medium of the web Interdisciplinary: Ling, CS, psych, math Help in communication With computers (ASR, TTS) With other humans (MT) Ambitious yet practical

5. 5 Goals of NLP Scientific Goal Identify the computational machinery needed for an agent to exhibit various forms of linguistic behavior Engineering Goal Design, implement, and test systems that process natural languages for practical applications

6. 6 Applications speech processing: get flight information or book a hotel over the phone information extraction: discover names of people and events they participate in, from a document machine translation: translate a document from one human language into another question answering: find answers to natural language questions in a text collection or database summarization: generate a short biography of Noam Chomsky from one or more news articles

7. 7 Reference Daniel Jurafsky James H. Martin An Introduction to Natural Language Processing, Computational Linguistics, and Speech Recognition Prentice-Hall, 2000

8. 8 Course contents… OverviewChapter (1)1 session Regular expressions & Automata Chapter (2)2 session Morphology & Finite-State Transducers (FSTs) Chapter (3)1-2 session Spelling checking (maybe)Chapter (5)2 session

9. 9 Course contents… N-gramsChapter (6)2 session HMM (maybe)Chapter (7)1 session Part-of-speech (POS) tagging Chapter (8)4 session Context-Free GrammarsChapter (9)2 session

10. 10 Course contents… ParsingChapter (10) 2 session Unification-based parsingChapter (11) 2 session Lexicalized & Probabilistic parsing Chapter (12) 2 session Machine TranslationChapter (21) and … 2 session

11. 11 Other Course Activities Maintenance the homepage of Course & NLP LAB Student Presentation (some subjects will be announced) Different projects (usually work on Persian language) Some Project implementation by Perl Language

12. 12 Evaluation 1 midterm exam : 5-6 degree 1 final term exam : 8 degree Paper presentation: 1-2 degree Some projects : 3-4 degree Some quizzes: 1 degree Some practices: 1 degree Paper publication: 1-4 added degree