Exploring complex vowels as phrase break correlates in a corpus of English speech with ProPOSEL, a prosody and POS English lexicon

Real-world knowledge of syntax is seen as integral to the machine learning task of phrase break prediction but there is a deficiency of a priori knowledge of prosody in both rule-based and data-driven classifiers. Speech recognition has established that pauses affect vowel duration in preceding words. Based on the observation that complex vowels occur at rhythmic junctures in poetry, we run significance tests on a sample of transcribed, contemporary British English speech and find a statistically significant correlation between complex vowels and phrase breaks. The experiment depends on automatic text annotation via ProPOSEL, a prosody and part-of-speech English lexicon. Copyright © 2009 ISCA

Preliminary Work on Speech Unit Selection Using Syntax Phonology Interface

This paper proposes an approach which uses a syntax-phonology interface to select the most appropriate speech units for a target sentence. The selection of the speech units is done by constructing the syntax-phonology tree structure of the target sentence. The construction of the syntax-phonology tree is adapted from the example-based parsing of UTMK machine translation

Prosodic phrase break prediction: problems in the evaluation of models against a gold standard

The goal of automatic phrase break prediction is to identify prosodic-syntactic boundaries in text which correspond to the way a native speaker might process or chunk that same text as speech. This is treated as a classification task in machine learning and output predictions from language models are evaluated against a ‘gold standard’: human-labelled prosodic phrase break annotations in transcriptions of recorded speech - the speech corpus. Despite the introduction of rigorous metrics such as precision and recall, the evaluation of phrase break models is still problematic because prosody is inherently variable; morphosyntactic analysis and prosodic annotations for a given text are not representative of the range of parsing and phrasing strategies available to, and exhibited by, native speakers. This article recommends creating automatically-generated POS tagged and prosodically annotated variants of a text to enrich the gold standard and enable more robust ‘noise-tolerant’ evaluation of language models

Complex vowels as boundary correlates in a multi-speaker corpus of spontaneous English speech

We have found empirical evidence of a correlation in English between words containing complex vowels (diphthongs and triphthongs) and ‘gold-standard’ phrase break annotations in datasets as apparently different as seventeenth-century verse and a Reith lecture transcript on economics from the late twentieth-century. Spontaneous speech in the form of BBC radio news reportage from the 1980s again exhibits this statistically significant correlation for five out of ten speakers, leading to speculation as to why speakers should fall into two distinct groups. The experiment depends on the automatic annotation of text with a priori knowledge from ProPOSEL, a prosody and part-of-speech English lexicon

On the automaticity of language processing

People speak and listen to language all the time. Given this high frequency of use, it is often suggested that at least some aspects of language processing are highly overlearned and therefore occur “automatically”. Here we critically examine this suggestion. We first sketch a framework that views automaticity as a set of interrelated features of mental processes and a matter of degree rather than a single feature that is all-or-none. We then apply this framework to language processing. To do so, we carve up the processes involved in language use according to (a) whether language processing takes place in monologue or dialogue, (b) whether the individual is comprehending or producing language, (c) whether the spoken or written modality is used, and (d) the linguistic processing level at which they occur, that is, phonology, the lexicon, syntax, or conceptual processes. This exercise suggests that while conceptual processes are relatively non-automatic (as is usually assumed), there is also considerable evidence that syntactic and lexical lower-level processes are not fully automatic. We close by discussing entrenchment as a set of mechanisms underlying automatization

ProPOSEL: a human-oriented prosody and PoS English lexicon for machine learning and NLP

ProPOSEL is a prosody and PoS English lexicon, purpose-built to integrate and leverage domain knowledge from several well-established lexical resources for machine learning and NLP applications. The lexicon of 104049 separate entries is in accessible text file format, is human and machine- readable, and is intended for open source distribution with the Natural Language ToolKit. It is therefore supported by Python software tools which transform ProPOSEL into a Python dictionary or associative array of linguistic concepts mapped to compound lookup keys. Users can also conduct searches on a subset of the lexicon and access entries by word class, phonetic transcription, syllable count and lexical stress pattern. ProPOSEL caters for a range of different cognitive aspects of the lexicon

Towards a machine-learning architecture for lexical functional grammar parsing

Data-driven grammar induction aims at producing wide-coverage grammars of human languages. Initial efforts in this field produced relatively shallow linguistic representations such as phrase-structure trees, which only encode constituent structure. Recent work on inducing deep grammars from treebanks addresses this shortcoming by also recovering non-local dependencies and grammatical relations. My aim is to investigate the issues arising when adapting an existing Lexical Functional Grammar (LFG) induction method to a new language and treebank, and find solutions which will generalize robustly across multiple languages. The research hypothesis is that by exploiting machine-learning algorithms to learn morphological features, lemmatization classes and grammatical functions from treebanks we can reduce the amount of manual specification and improve robustness, accuracy and domain- and language -independence for LFG parsing systems. Function labels can often be relatively straightforwardly mapped to LFG grammatical functions. Learning them reliably permits grammar induction to depend less on language-specific LFG annotation rules. I therefore propose ways to improve acquisition of function labels from treebanks and translate those improvements into better-quality f-structure parsing. In a lexicalized grammatical formalism such as LFG a large amount of syntactically relevant information comes from lexical entries. It is, therefore, important to be able to perform morphological analysis in an accurate and robust way for morphologically rich languages. I propose a fully data-driven supervised method to simultaneously lemmatize and morphologically analyze text and obtain competitive or improved results on a range of typologically diverse languages

Coherence in Machine Translation

Coherence ensures individual sentences work together to form a meaningful document. When properly translated, a coherent document in one language should result in a coherent document in another language. In Machine Translation, however, due to reasons of modeling and computational complexity, sentences are pieced together from words or phrases based on short context windows and with no access to extra-sentential context. In this thesis I propose ways to automatically assess the coherence of machine translation output. The work is structured around three dimensions: entity-based coherence, coherence as evidenced via syntactic patterns, and coherence as evidenced via discourse relations. For the first time, I evaluate existing monolingual coherence models on this new task, identifying issues and challenges that are specific to the machine translation setting. In order to address these issues, I adapted a state-of-the-art syntax model, which also resulted in improved performance for the monolingual task. The results clearly indicate how much more difficult the new task is than the task of detecting shuffled texts. I proposed a new coherence model, exploring the crosslingual transfer of discourse relations in machine translation. This model is novel in that it measures the correctness of the discourse relation by comparison to the source text rather than to a reference translation. I identified patterns of incoherence common across different language pairs, and created a corpus of machine translated output annotated with coherence errors for evaluation purposes. I then examined lexical coherence in a multilingual context, as a preliminary study for crosslingual transfer. Finally, I determine how the new and adapted models correlate with human judgements of translation quality and suggest that improvements in general evaluation within machine translation would benefit from having a coherence component that evaluated the translation output with respect to the source text