1. For Wednesday No reading Homework –Chapter 23, exercise 15 –Process: 1.Create 5 sentences 2.Select a language 3.Translate each sentence into that language and back to English – look at the result 4.Translate the results into the other language and back to English again 5.Pick a different language and repeat steps 3 and 4 6.Discuss –I want to see all of the English sentences and the discussion. You do not have to do the last part even if you do know another language.

2. Program 5 Any questions?

3. Machine Translation Best systems must use all levels of NLP Semantics must deal with the overlapping senses of different languages Both understanding and generation Advantage in learning: bilingual corpora exist--but we often want some tagging of intermediate relationships Additional issue: alignment of corpora

4. Approaches to MT Lots of hand-built systems Some learning used Probably most use a fair bit of syntactic and semantic analysis Some operate fairly directly between texts

5. Generation Producing a syntactically “good” sentence Interesting issues are largely in choices –What vocabulary to use –What level of detail is appropriate –Determining how much information to include

6. Ethical issues in AI What are the benefits and risks in attempting to develop AI programs?