Modeling Lexically Divergent Paraphrases in Twitter (and Shakespeare!)

Wei Xu (Penn)

ABSTRACT   

Paraphrases are alternative linguistic expressions of the same meaning. 
Identifying paraphrases is fundamental to many natural language processing
tasks and has been extensively studied for the standard contemporary English.
In this talk I will present MULTIP (Multi-instance Learning Paraphrase Model),
a joint word-sentence alignment model suited to identify paraphrases within 
the noisy user-generated texts on Twitter. The model infers latent word-level 
paraphrase anchors from only sentence-level annotations during learning. This 
is a major departure from previous approaches that rely on lexical or 
distributional similarities over sentence pairs. By reducing the dependence 
on word overlap as evidence of paraphrase, our approach identifies more 
lexically divergent expressions with equivalent meaning. For experiments, 
we constructed a Twitter Paraphrase Corpus of about 19,000 sentences using 
a novel and efficient crowdsourcing methodology. Our new approach improves 
the state-of-the-art performance of a method that combines a latent space model
with a feature-based supervised classifier. I will also present findings on
paraphrasing between standard English and Shakespearean styles.

Joint work with Chris Callison-Burch (UPenn), Bill Dolan (MSR), 
Alan Ritter (OSU), Yangfeng Ji (GaTech), Colin Cherry (NRC) and 
Ralph Grishman (NYU).

BIO

Wei Xu is a postdoc in Computer and Information Science Department at University
of Pennsylvania, working with Chris Callison-Burch. Her research focuses on 
paraphrases, social media and information extraction. She received her PhD in 
Computer Science from New York University. She is organizing the SemEval-2015 
shared task on Paraphrase and Semantic Similarity in Twitter.  During her PhD,
she visited University of Washington for two years and interned at Microsoft 
Research, ETS and Amazon.com.