Phonotactic probability and phonotactic constraints :processing and lexical segmentation by Arabic learners of English as a foreign language

PhD ThesisA fundamental skill in listening comprehension is the ability to recognize words. The ability to accurately locate word boundaries(i . e. to lexically segment) is an important contributor to this skill. Research has shown that English native speakers use various cues in the signal in lexical segmentation. One such cue is phonotactic constraints; more specifically, the presence of illegal English consonant sequences such as AV and MY signals word boundaries. It has also been shown that phonotactic probability (i. e. the frequency of segments and sequences of segments in words) affects native speakers' processing of English. However, the role that phonotactic probability and phonotactic constraints play in the EFL classroom has hardly been studied, while much attention has been devoted to teaching listening comprehension in EFL. This thesis reports on an intervention study which investigated the effect of teaching English phonotactics upon Arabic speakers' lexical segmentation of running speech in English. The study involved a native English group (N= 12), a non-native speaking control group (N= 20); and a non-native speaking experimental group (N=20). Each of the groups took three tests, namely Non-word Rating, Lexical Decision and Word Spotting. These tests probed how sensitive the subjects were to English phonotactic probability and to the presence of illegal sequences of phonemes in English and investigated whether they used these sequences in the lexical segmentation of English. The non-native groups were post-tested with the -same tasks after only the experimental group had been given a treatment which consisted of explicit teaching of relevant English phonotactic constraints and related activities for 8 weeks. The gains made by the experimental group are discussed, with implications for teaching both pronunciation and listening comprehension in an EFL setting.Qassim University, Saudi Arabia

A role for the developing lexicon in phonetic category acquisition

Infants segment words from fluent speech during the same period when they are learning phonetic categories, yet accounts of phonetic category acquisition typically ignore information about the words in which sounds appear. We use a Bayesian model to illustrate how feedback from segmented words might constrain phonetic category learning by providing information about which sounds occur together in words. Simulations demonstrate that word-level information can successfully disambiguate overlapping English vowel categories. Learning patterns in the model are shown to parallel human behavior from artificial language learning tasks. These findings point to a central role for the developing lexicon in phonetic category acquisition and provide a framework for incorporating top-down constraints into models of category learning

Learning interaction between statistical learning experiments

When participants in a statistical learning paradigm are asked to learn from two incompatible or competing inputs, they often fail to learn from one or both inputs. This study presents the results of two experiments that were both completed by one group of typically developing four-year-old children. One experiment targeted word-medial consonant patterns (phonotactics), whereas the other targeted strong-weak and weak-strong stress patterns (prosody). The order of the experiments was critical for learning outcomes in the phonotactics experiment: When children learned phonotactics first, their production accuracy increased following exposure to a high frequency input. When children learned phonotactics second, however, their production accuracy dropped when they were exposed to the high frequency input. Results from the prosody experiment were inconclusive, with limited evidence of any learning effect. Overall, the results suggest that children may conflate learning experiences, and patterns learned from an initial experimental input compete with patterns in a subsequent experiment. When considering natural language acquisition, the results suggest that an isolated episode of learning may lead to generalizations that are incompatible with later input, and possibly, with larger patterns in the language.Communication Sciences and Disorder

THE USE OF SEGMENTATION CUES IN SECOND LANGUAGE LEARNERS OF ENGLISH

This dissertation project examined the influence of language typology on the use of segmentation cues by second language (L2) learners of English. Previous research has shown that native English speakers rely more on sentence context and lexical knowledge than segmental (i.e. phonotactics or acoustic-phonetics) or prosodic cues (e.g., word stresss) in native language (L1) segmentation. However, L2 learners may rely more on segmental and prosodic cues to identify word boundaries in L2 speech since it may require high lexical and syntactic proficiency in order to use lexical cues efficiently. The goal of this dissertation was to provide empirical evidence for the Revised Framework for L2 Segmentation (RFL2) which describes the relative importance of different levels of segmentation cues. Four experiments were carried out to test the hypotheses made by RFL2. Participants consisted of four language groups including native English speakers and L2 learners of English with Mandarin, Korean, or Spanish L1s. Experiment 1 compared the use of stress cues and lexical knowledge while Experiment 2 compared the use of phonotactic cues and lexical knowledge. Experiment 3 compared the use of phonotactic cues and semantic cues while Experiment 4 compared the use of stress cues and sentence context. Results showed that L2 learners rely more on segmental cues than lexical knowledge or semantic cues. L2 learners showed cue interaction in both lexical and sublexical levels whereas native speakers appeared to use the cues independently. In general, L2 learners appeared to have acquired sensitivity to the segmentation cues used in L2, although they still showed difficulty with specific aspects in each cue based on L1 characteristics. The results provided partial support for RFL2 in which L2 learners' use of sublexical cues was influenced by L1 typology. The current dissertation has important pedagogical implication as findings may help identify cues that can facilitate L2 speech segmentation and comprehension

Epenthetic vowels in Japanese: A perceptual illusion?

In four cross-linguistic experiments comparing French and Japanese hearers, we found that the phonotactic properties of Japanese (very reduced set of syllable types) induce Japanese listeners to perceive ``illusory'' vowels inside consonant clusters in VCCV stimuli. In Experiments 1 and 2, we used a continuum of stimuli ranging from no vowel (e.g. ebzo) to a full vowel between the consonants (e.g. ebuzo). Japanese, but not French participants, reported the presence of a vowel [u] between consonants, even in stimuli with no vowel. A speeded ABX discrimination paradigm was used in Experiments 3 and 4, and revealed that Japanese participants had trouble discriminating between VCCV and VCuCV stimuli. French participants, in contrast had problems discriminating items that differ in vowel length (ebuzo vs. ebuuzo), a distinctive contrast in Japanese but not in French. We conclude that models of speech perception have to be revised to account for phonotactically-based assimilations

The interaction between temporal grouping and phonotactic chunking in short-term serial order memory for novel verbal sequences

The current study investigated the ways long-term memory contributes to short-term serial order memory of novel verbal sequences, focusing on long-term knowledge of bi-element frequency, that is, co-occurrence frequency of two consecutive elements in a linguistic environment. Participants performed two types of immediate serial recall of nine-element (nine-mora) sequences: low bi-mora frequency sequences where all eight associations between the nine morae were low frequency, and mixed bi-mora frequency sequences, with high-frequency associations for six of the eight bi-morae. Experiment 1 confirmed the bi-directional bi-mora frequency effect, meaning better recall performance for morae having high-frequency association with either the preceding mora (forward association) or the following mora (backward association). In Experiment 2, two temporal pauses were inserted in each list to disrupt high-frequency associations with the preceding mora or the following mora. The results showed that the bi-element frequency effect diminished when the high-frequency backward association was disrupted but the effect remained when the high-frequency forward association was disrupted. We discuss possible mechanisms underlying the asymmetric influence of temporal pauses on interactions between short-term memory and linguistic long-term memory

Segmentation of British Sign Language (BSL): Mind the gap!

This study asks how users of British Sign Language (BSL) recognize individual signs in connected sign sequences. We examined whether this is achieved through modality-specific or modality-general segmentation procedures. A modality-specific feature of signed languages is that, during continuous signing, there are salient transitions between sign locations. We used the sign-spotting task to ask if and how BSL signers use these transitions in segmentation. A total of 96 real BSL signs were preceded by nonsense signs which were produced in either the target location or another location (with a small or large transition). Half of the transitions were within the same major body area (e.g., head) and half were across body areas (e.g., chest to hand). Deaf adult BSL users (a group of natives and early learners, and a group of late learners) spotted target signs best when there was a minimal transition and worst when there was a large transition. When location changes were present, both groups performed better when transitions were to a different body area than when they were within the same area. These findings suggest that transitions do not provide explicit sign-boundary cues in a modality-specific fashion. Instead, we argue that smaller transitions help recognition in a modality-general way by limiting lexical search to signs within location neighbourhoods, and that transitions across body areas also aid segmentation in a modality-general way, by providing a phonotactic cue to a sign boundary. We propose that sign segmentation is based on modality-general procedures which are core language-processing mechanisms