Natasha Warner

Laboratory Phonology 7

This collection of recent papers in Laboratory Phonology approaches phonological theory from several different empirical directions. Psycholinguistic research into the perception and production of speech has produced results that challenge current conceptions about phonological structure. Field work studies provide fresh insights into the structure of phonological features, and the phonology-phonetics interface is investigated in phonetic research involving both segments and prosody, while the role of underspecification is put to the test in automatic speech recognition.

Incomplete neutralization and other sub-phonemic durational differences in production and perception: Evidence from Dutch

Abstract Words which are expected to contain the same surface string of segments may, under identical prosodic circumstances, sometimes be realized with slight differences in duration. Some researchers have attributed such effects to differences in the words’ underlying forms (incomplete neutralization), while others have suggested orthographic influence and extremely careful speech as the cause. In this paper, we demonstrate such sub-phonemic durational differences in Dutch, a language which some past research has found not to have such effects. Past literature has also shown that listeners can often make use of incomplete neutralization to distinguish apparent homophones. We extend perceptual investigations of this topic, and show that listeners can perceive even durational differences which are not consistently observed in production. We further show that a difference which is primarily orthographic rather than underlying can also create such durational differences. We conclude that a wide variety of factors, in addition to underlying form, can induce speakers to produce slight durational differences which listeners can also use in perception.

Japanese Mora-Timing: A Review

Japanese is often called a ‘mora-timed’ language, and contrasted with ‘stress- timed’ or ‘syllable-timed’ languages. The definition of what constitutes mora-timing has undergone several revisions, and a wide variety of experimental evidence both for and against mora-timing has been presented. This article reviews the hypotheses, the means of testing them, and the results of nearly 40 years of experimental work on mora-timing in Japanese, and suggests directions for future work in this area.

An introduction to reduced pronunciation variants [Editorial]

Words are often pronounced very differently in formal speech than in everyday conversations. In conversational speech, they may contain weaker segments, fewer sounds, and even fewer syllables. The English word yesterday, for instance, may be pronounced as [jɛʃeɪ]. This article forms an introduction to the phenomenon of reduced pronunciation variants and to the eight research articles in this issue on the characteristics, production, and comprehension of these variants. We provide a description of the phenomenon, addressing its high frequency of occurrence in casual conversations in various languages, the gradient nature of many reduction processes, and the intelligibility of reduced variants to native listeners. We also describe the relevance of research on reduced variants for linguistic and psychological theories as well as for applications in speech technology and foreign language acquisition. Since reduced variants occur more often in spontaneous than in formal speech, they are hard to study in the laboratory under well controlled conditions. We discuss the advantages and disadvantages of possible solutions, including the research methods employed in the articles in this special issue, based on corpora and experiments. This article ends with a short overview of the articles in this issue.

Unfolding of phonetic information over time: A database of Dutch diphone perception

We present the results of a large-scale study on speech perception, assessing the number and type of perceptual hypotheses which listeners entertain about possible phoneme sequences in their language. Dutch listeners were asked to identify gated fragments of all 1179 diphones of Dutch, providing a total of 488,520 phoneme categorizations. The results manifest orderly uptake of acoustic information in the signal. Differences across phonemes in the rate at which fully correct recognition was achieved arose as a result of whether or not potential confusions could occur with other phonemes of the language (long with short vowels, affricates with their initial components, etc.). These data can be used to improve models of how acoustic-phonetic information is mapped onto the mental lexicon during speech comprehension.

Orthographic vs. morphological incomplete neutralization effects

Abstract This study, following up on work on Dutch by Warner, Jongman, Sereno, and Kemps (2004. Journal of Phonetics, 32, 251–276), investigates the influence of orthographic distinctions and underlying morphological distinctions on the small sub-phonemic durational differences that have been called incomplete neutralization. One part of the previous work indicated that an orthographic geminate/singleton distinction could cause speakers to produce an incomplete neutralization effect. However, one interpretation of the materials in that experiment is that they contain an underlying difference in the phoneme string at the level of concatenation of morphemes, rather than just an orthographic difference. Thus, the previous effect might simply be another example of incomplete neutralization of a phonemic distinction. The current experiment, also on Dutch, uses word pairs which have the same underlying morphological contrast, but do not differ in orthography. These new materials show no incomplete neutralization, and thus support the hypothesis that orthography, but not underlying morphological differences, can cause incomplete neutralization effects.

The phonological status of Dutch epenthetic schwa

In this paper, we use articulatory measures to determine whether Dutch schwa epenthesis is an abstract phonological process or a concrete phonetic process depending on articulatory timing. We examine tongue position during /l/ before underlying schwa and epenthetic schwa and in coda position. We find greater tip raising before both types of schwa, and greater dorsal lowering in coda position, indicating light /l/ in the former and dark /l/ in the latter. We argue that the ability of epenthetic schwa to condition the /l/ alternation shows that Dutch schwa epenthesis is an abstract phonological process involving insertion of some unit, and cannot be accounted for within Articulatory Phonology.

The role of the mora in the timing of spontaneous Japanese speech

This study investigates whether the mora is used in controlling timing in Japanese speech, or is instead a structural unit in the language not involved in timing. Unlike most previous studies of mora-timing in Japanese, this article investigates timing in spontaneous speech. Predictability of word duration from number of moras is found to be much weaker than in careful speech. Furthermore, the number of moras predicts word duration only slightly better than number of segments. Syllable structure also has a significant effect on word duration. Finally, comparison of the predictability of whole words and arbitrarily truncated words shows better predictability for truncated words, which would not be possible if the truncated portion were compensating for remaining moras. The results support an accumulative model of variance with a final lengthening effect, and do not indicate the presence of any compensation related to mora-timing. It is suggested that the rhythm of Japanese derives from several factors about the structure of the language, not from durational compensation.

Acoustic characteristics of ejectives in Ingush

The purpose of the paper is to investigate acoustic characteristics which distinguish ejectives from pulmonic stops in Ingush (a Northeast Caucasian language), and to compare Ingush ejectives to those of other languages. The articulation of ejectives is relatively well understood, but their acoustic effects are less clear. Working with a native speaker of Ingush, ejectives and pulmonic voiceless stops were compared for VOT, closure duration, and post-burst power; and pitch, amplitude, and voice quality of the following vowel. Ingush results are compared to published descriptions of ejectives in several other languages. Ingush ejectives do not have all the same acoustic features as any other language studied. The characteristics of ejectives vary with each language, and do not pattern together to form just two types of ejectives, as has been claimed based on binary comparisons.

Processing missing vowels : Allophonic processing in Japanese

The acoustic realisation of a speech sound varies, often showing allophonic variation triggered by surrounding sounds. Listeners recognise words and sounds well despite such variation, and even make use of allophonic variability in processing. This study reports five experiments on processing of the reduced/unreduced allophonic alternation of Japanese high vowels. The results show that listeners use phonological knowledge of their native language during phoneme processing and word recognition. However, interactions of the phonological and acoustic effects differ in these two processes. A facilitatory phonological effect and an inhibitory acoustic effect cancel one another out in phoneme processing; while in word recognition, the facilitatory phonological effect overrides the inhibitory acoustic effect. Four potential models of the processing of allophonic variation are discussed. The results can be accommodated in two of them, but require additional assumptions or modifications to the models, and primarily support lexical specification of allophonic variability.