Spandana Gella

POS Tagging of English-Hindi Code-Mixed Social Media Content

Code-mixing is frequently observed in user generated content on social media, especially from multilingual users. The linguistic complexity of such content is compounded by presence of spelling variations, transliteration and non-adherance to formal grammar. We describe our initial efforts to create a multi-level annotated corpus of Hindi-English codemixed text collated from Facebook forums, and explore language identification, back-transliteration, normalization and POS tagging of this data. Our results show that language identification and transliteration for Hindi are two major challenges that impact POS tagging accuracy.

Learning Word Sense Distributions, Detecting Unattested Senses and Identifying Novel Senses Using Topic Models

Unsupervised word sense disambiguation (WSD) methods are an attractive approach to all-words WSD due to their non-reliance on expensive annotated data. Unsupervised estimates of sense frequency have been shown to be very useful for WSD due to the skewed nature of word sense distributions. This paper presents a fully unsupervised topic modelling-based approach to sense frequency estimation, which is highly portable to different corpora and sense inventories, in being applicable to any part of speech, and not requiring a hierarchical sense inventory, parsing or parallel text. We demonstrate the effectiveness of the method over the tasks of predominant sense learning and sense distribution acquisition, and also the novel tasks of detecting senses which aren’t attested in the corpus, and identifying novel senses in the corpus which aren’t captured in the sense inventory.

One Sense per Tweeter ... and Other Lexical Semantic Tales of Twitter

In recent years, microblogs such as Twitter have emerged as a new communication channel. Twitter in particular has become the target of a myriad of content-based applications including trend analysis and event detection, but there has been little fundamental work on the analysis of word usage patterns in this text type. In this paper — inspired by the one-sense-perdiscourse heuristic of Gale et al. (1992) — we investigate user-level sense distributions, and detect strong support for “one sense per tweeter”. As part of this, we construct a novel sense-tagged lexical sample dataset based on Twitter and a web corpus.

Unsupervised Visual Sense Disambiguation for Verbs using Multimodal Embeddings

We introduce a new task, visual sense disambiguation for verbs: given an image and a verb, assign the correct sense of the verb, i.e., the one that describes the action depicted in the image. Just as textual word sense disambiguation is useful for a wide range of NLP tasks, visual sense disambiguation can be useful for multimodal tasks such as image retrieval, image description, and text illustration. We introduce VerSe, a new dataset that augments existing multimodal datasets (COCO and TUHOI) with sense labels. We propose an unsupervised algorithm based on Lesk which performs visual sense disambiguation using textual, visual, or multimodal embeddings. We find that textual embeddings perform well when gold-standard textual annotations (object labels and image descriptions) are available, while multimodal embeddings perform well on unannotated images. We also verify our findings by using the textual and multimodal embeddings as features in a supervised setting and analyse the performance of visual sense disambiguation task. VerSe is made publicly available and can be downloaded at: this https URL