Katerina Nicolaidis

Temporal and spatial aspects of lingual coarticulation in /kl/ sequences: a cross-linguistic investigation.

Temporal and spatial aspects of lingual coarticulation in /kl/ clusters in intervocalic position (VklV) were investigated in six European languages: Catalan, English, French, German, Italian, and Swedish. Three speakers of each language repeated a set of real words and nonsense items five times. Temporal overlap of /k/ and /l/ gestures, as represented by a numerical “overlap index”, was interpreted as tongue-tip/tongue-body coarticulation, and was measured from electropalatographic and airflow records. Results revealed several language-specific features. For example, the tendency to overlap was different for the six languages. All the languages except Swedish showed some instances of overlap, and Catalan showed the strongest tendency. The vowel environment also had a significant effect: The presence of an open back vowel in V1 and V2 positions increased the tendency for overlap to occur. However, there was no statistically significant difference in overlap between nonsense and real words. Spatial information from EPG data showed that articulatory placement of the tongue-body gesture was more retracted in a /kl/ cluster compared to a singleton consonant. All the languages under investigation showed this phenomenon. These findings are discussed in terms of possible constraints operating between the tip/blade and tongue-body systems.

An electropalatographic study of Greek spontaneous speech

This paper aims to examine spatio-temporal variability during the production of the lingual consonants /t, d, s, z, k, g l, n, XXX/ in a sample of Greek spontaneous speech. It provides a description of the range of segmental variability and explores the relationship between articulatory and temporal variability. It also discusses instances of common connected speech processes including assimilations and deletions. Data from two Greek speakers producing a monologue was recorded with the technique of electropalatography (Reading EPG system). The results indicated that segmental variability ranges over a continuum from over-articulated to under-articulated forms, i.e. fully articulated tokens to very open articulations. In addition, duration dependent variability was found to be a function of the production characteristics of the consonant. Evidence of both gradient and categorical changes in spontaneous speech were suggested by the data and are discussed with reference to current theoretical frameworks.

Articulatory Variability during Consonant Production by Greek Speakers with Hearing Impairment: An Electropalatographic Study.

This study uses the technique of electropalatography to investigate lingualpalatal contact patterns during the production of the consonants /t, k, s, x, n, l, [symbol - see pdf]/ by four Greek speakers with profound hearing impairment and with differences in the intelligibility of their speech. The study provides a detailed description of their tongue-palate contact patterns and discusses some of the articulatory parameters that differentiate consonantal articulation between speakers with normal hearing and hearing impairment. Deviant patterns were found for the majority of consonants and involved substitutions, distortions, amd epenthesis of segments. The segments that deviated from normal for all speakers were the fricative /s/, the palatal obstruents [c] and [c¸], and the tap [[symbol - see pdf]]. Significant differences in articulatory variability during consonantal production were also found. The study discusses deviant patterns in consonant production in relation to the differences in intelligibility among the speakers and with reference to data from previous studies. The issues discussed in this study and the methodology adopted fall within the line of research carried out by Bill Hardcastle and his colleagues at QMUC over the years. His work for the development of electropalatography and his research on speech production have provided important insights into the articulatory characteristics of normal and disordered speech. This paper is dedicated to him with my best wishes for the continuation of an influential, creative and productive career in the field.

Acquisition of initial /s/-stop and stop-/s/sequences in Greek.

Previous work on children’s acquisition of complex sequences points to a tendency for affricates to be acquired before clusters, but there is no clear evidence of a difference in order of acquisition between clusters with /s/ that violate the Sonority Sequencing Principle (SSP), such as /s/ followed by stop in onset position, and other clusters that obey the SSP. One problem with studies that have compared the acquisition of SSP-obeying and SSP-violating clusters is that the component sounds in the two types of sequences were different. This paper examines the acquisition of initial /s/-stop and stop-/s/ sequences by sixty Greek children aged 2 through 5 years. Results showed greater accuracy for the /s/-stop relative to the stop-/s/ sequences, but no difference in accuracy between /ts/, which is usually analyzed as an affricate in Greek, and the other stop-/s/ sequences. Moreover, errors for the /s/-stop sequences and /ts/ primarily involved stop substitutions, whereas errors for /ps/ and /ks/ were more variable and often involved fricative substitutions, a pattern which may have a perceptual explanation. Finally, /ts/ showed a distinct temporal pattern relative to the stop-/s/ clusters /ps/ and /ks/, similar to what has been reported for productions of Greek adults.

Acoustic characteristics of vowels produced by Greek intelligible speakers with profound hearing impairment I: Examination of vowel space

Abstract Purpose: The study examines F1, F2 and F3 formant frequencies of vowels produced by six Greek intelligible speakers with profound hearing impairment and six speakers with normal hearing (three male and three female in each group). Method: The formant frequencies are measured in words of the form /ʹpVCV/ where V = /i, , , , u/ and C = /p, t, k, s/. The study examines differences in formant frequencies between the two groups and as a function of gender. Three measures are calculated to examine the area of the vowel space and differences along the F1 and F2 axes between the groups and genders. Result: The results show that the vowel space produced by the speakers with hearing impairment is considerably reduced. Greater reduction was evident for F2 compared to F1. Restricted formant frequency ranges and relatively large variation along F1 and/or F2 for selected vowels resulted in overlap among vowel categories. F3 frequencies were systematically lower and showed greater variation for the speakers with hearing impairment. Conclusion: The paper discusses findings with reference to perceptual and production constraints affecting the speech of individuals with hearing impairment.

Acoustic characteristics of vowels produced by Greek intelligible speakers with profound hearing impairment II: The influence of stress and context

Abstract Purpose: The present paper examines the influence of stress and context on selected acoustic characteristics of vowels produced by six adult Greek intelligible speakers with profound hearing impairment and six speakers with normal hearing (three males and three females in each group). Method: F1, F2 and F3 formant frequencies and the duration of vowels are measured in words of the form /′pVCV/ with V = /i, ɛ, ɐ, ɔ, u/ and C = /p, t, k, s/. Variation in these parameters due to context and stress is reported for the two genders. A co-articulatory measure and three measures that examine the area of the vowel space and differences along the F1 and F2 axes are calculated. Result: The results show a reduction of the vowel space in the unstressed condition for both groups, while vowel duration was found to be significantly longer in this condition for the speakers with hearing impairment. In addition, smaller C-to-V carryover co-articulatory effects were found for the speakers with hearing impairment. Conclusion: Findings are discussed within the framework of perceptual and production constraints in hearing impairment and with reference to current models of co-articulation.

Aspects of spatio-temporal variability during consonant production by Greek speakers with hearing impairment

This paper investigates spatio‐temporal variability during the production of the lingual consonants /t, k, s, x, n, l, ▒/ by four Greek speakers with profound hearing impairment and with differences in the intelligibility of their speech. It examines important factors that have been documented to influence intelligibility, i.e. durational variability, articulatory (token‐to‐token) variability, and coarticulatory patterns. The technique of electropalatography was used to record tongue‐palate contact patterns during consonant production in order to examine differences in articulatory variability among speakers and in V‐to‐C coarticulatory effects. The study reports durational differences in consonant production between speakers with hearing impairment and normal hearing and investigates the relationship between token‐to‐token variability in tongue‐palate contact patterns and duration. The results indicate a negative relationship between duration and variability, i.e. as segmental duration decreases there is an increase in variability in tongue‐palate contact patterns. Significant speaker‐dependent differences in duration, articulatory variability and coarticulatory patterns are reported and are discussed in relation to differences in intelligibility among the speakers with hearing impairment.

Coarticulatory dynamics in Greek disyllables produced by young adults with and without hearing loss

ABSTRACT Hearing loss affects both speech perception and production with detrimental effects on various speech characteristics including coarticulatory dynamics. The aim of the present study is to explore consonant-to-vowel (C-to-V) and vowel-to-vowel (V-to-V) coarticulation in magnitude, direction and temporal extent in the speech of young adult male and female speakers of Greek with normal hearing (NH) and hearing impairment (HI). Nine intelligible speakers with profound HI, using conventional hearing aids, and five speakers with NH produced /pV1CV2/ disyllables, with the point vowels /i, a, u/ and the consonants /p, t, s/, stressed either on the first or the second syllable. Formant frequencies F1 and F2 were measured in order to examine C-to-V effects at vowel midpoint and V-to-V effects at vowel onset, midpoint and offset. The acoustic and statistical analyses revealed similarities but also significant differences regarding coarticulatory patterns of the two groups. Interestingly, prevalence of anticipatory coarticulation effects in alveolar contexts was observed for speakers with HI. Findings are interpreted on account of possible differences in articulation strategies between the two groups and with reference to current coarticulatory models.