Dr. David Mortensen (Carnegie Mellon University) will give a colloquium online on September 20 – 3:30-5:00pm, 2024.
To register please use the registration link.
Title: Extension is all you need (but sometimes good intensions help too)
Abstract: The philosophical distinction between intension and extension is relevant to many problems in mathematics and the sciences (including linguistics and computational linguistics). Intension refers to the definitional properties of a construct and extension refers to how a construct is manifest in the world.
This talk describes two computational linguistic studies which present seemingly opposed perspectives on the question of extension versus intension. The first concerns a family of sound patterns that are difficult to describe if one starts with articulatory features—phonological ordering effects in elaborate expressions and coordinate compounds. We show that these patterns, while frequently phonetically arbitrary, can be very robust and that they are learnable from surface distributions (by simple decision trees and SVMs as well as CNNs and LSTMs) without intensional supervision. We also show that there is an evolutionary pathway between an articulatorily coherent origin of these patterns and their current extension.
In the second study, we demonstrate that neural phonetic embedding methods supervised with universal articulatory features outperform methods without such supervision on many tasks in a comprehensive evaluation suite we have developed. On the other hand, purely data-driven approaches work best on tasks that are not defined in terms of articulatory features. These experiments suggest that intensional representations are useful just in case there is a clear mapping between intension and extension and adequate extensional representations are not available (as with the language-agnostic tasks in our test suite).
Bio: David R. Mortensen is an Assistant Research Professor in the Language Technologies Institute at Carnegie Mellon University. He received his PhD in Linguistics from the University of California at Berkeley and held a position as an Assistant Professor of Linguistics at the University of Pittsburgh before transitioning to CMU, computational linguistics, and NLP. His work sits at the intersection between natural language processing, speech processing, phonology, morphology, and language change.
