Speaker: Marie-Catherine de Marneffe, Department of Linguistics
Time: MONDAY 10/28, 4pm-5pm
Location: Dreese Lab 480
Title: Do you know that there’s still a chance? Identifying speaker commitment for natural language understanding.
When we communicate, we infer a lot beyond the literal meaning of the words we hear or read. In particular, our understanding of an utterance depends on assessing the extent to which the speaker stands by the event she describes. An unadorned declarative like “The cancer has spread” conveys firm speaker commitment of the cancer having spread, whereas “There are some indicators that the cancer has spread” imbues the claim with uncertainty. It is not only the absence vs. presence of embedding material that determines whether or not a speaker is committed to the event described: from (1) we will infer that the speaker is committed to there *being* war, whereas in (2) we will infer the speaker is committed to relocating species *not being* a panacea, even though the clauses that describe the events in (1) and (2) are both embedded under “(s)he doesn’t believe”.
(1) The problem, I’m afraid, with my colleague here, he really doesn’t believe that it’s war.
(2) Transplanting an ecosystem can be risky, as history shows. Hellmann doesn’t believe that relocating species threatened by climate change is a panacea.
In this talk, I will first illustrate how looking at pragmatic information of what speakers are committed to can improve NLP applications. Previous work has tried to predict the outcome of contests (such as the Oscars or elections) from tweets. I will show that by distinguishing tweets that convey firm speaker commitment toward a given outcome (e.g., “Dunkirk will win Best Picture in 2018″) from ones that only suggest the outcome (e.g., “Dunkirk might have a shot at the 2018 Oscars”) or tweets that convey the negation of the event (“Dunkirk is good but not academy level good for the Oscars”), we can outperform previous methods. Second, I will evaluate current models of speaker commitment, using the CommitmentBank, a dataset of naturally occurring discourses developed to deepen our understanding of the factors at play in identifying speaker commitment. We found that a linguistically informed model outperforms a LSTM-based one, suggesting that linguistic knowledge is needed to achieve robust language understanding. Both models however fail to generalize to the diverse linguistic constructions present in natural language, highlighting directions for improvement.
Bio: Marie-Catherine de Marneffe is an Associate Professor in Linguistics at The Ohio State University. She received her PhD from Stanford University in December 2012 under the supervision of Christopher D. Manning. She is developing computational linguistic methods that capture what is conveyed by speakers beyond the literal meaning of the words they say. Primarily she wants to ground meanings in corpus data, and show how such meanings can drive pragmatic inference. She has also worked on Recognizing Textual Entailment and contributed to defining the Stanford Dependencies and the Universal Dependencies representations. She is the recipient of a Google Research Faculty award, NSF CRII award and recently a NSF CAREER award. She serves as a member of the NAACL board.