Natural language research announcements

[Julia Hockenmaier <juliahmr AT uiuc.edu>]

Computer Science Distinguished Lectureship Series

Bayesian models of language acquisition,
Or, Where do the rules come from?

Mark Johnson, Brown University
Monday April 7 2008, 4:00pm
1404 Siebel Center, Department of Computer Science, UIUC


Each human language contains an astronomically large (if not unbounded) 
number of different sentences. How can something so large and complex 
possibly be learned? Over the past decade and a half we've figured out 
how to define probability distributions over grammars and the linguistic 
structures they generate, opening up the possibility of Bayesian models 
of language acquisition. Bayesian approaches are particularly attractive 
because they can exploit "prior" (e.g., innate) knowledge as well as 
statistical generalizations from the input. Bayesian learners have two 
major advantages over other approaches. First, because the 
generalizations they learn and the prior knowledge they utilize are both 
expressed in terms of explicit representations, it is clear what is 
learned and what information is exploited during learning. Second, 
because of the "curse of dimensionality", learners that identify and 
exploit structural properties of their input seem to be the only ones 
that have a chance of "scaling up" to learn real languages. This talk 
describes Bayesian methods for learning Context-Free Grammars and a 
generalization of them that we call Adaptor Grammars, and applies them 
to problems of morphological acquisition and word segmentation.

Bio:

Mark Johnson is Professor of Cognitive and Linguistic Sciences and 
Computer Science at Brown University. After getting his BSc (Hons) from 
the University of Sydney in Australia, he obtained an MA from UCSD and a 
PhD from Stanford. He held a postdoctoral fellowship at MIT. He has been 
a visiting researcher at the University of Stuttgart, the Xerox Research 
Centre in Grenoble, CSAIL at MIT and Microsoft Research. He was 
President of the Association for Computational Linguistics in 2003.

http://www.cog.brown.edu/~mj/


Note:
We still have a few slots on Mark's schedule. If you want to meet him, 
please email Ronda Pellegrini (rpellegr AT cs.uiuc.edu).