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Children who receive cochlear implants (CIs) demonstrate considerable variability in speech sound production. Investigations focused on speech sound development in children with CIs have shown initial accelerated growth, followed by a plateau where consonant order of acquisition generally mirrors that of NH children, but is slower (Blamey, Barry, & Pascale, 2001; Serry & Blamey, 1999; Spencer & Guo, 2013). A notable exception to this pattern, /t/, has been shown to be acquired later-than normal in several investigations (Blamey et al., 2001; Chin, 2003; Ertmer, True Kloiber, Jongmin, Connell Kirleis, & Bradford, 2012). The primary purpose of this investigation was to 1) examine the accuracy of /t/ productions in children with CIs and 2) quantify subtle phonetic differences in correctly produced consonants and substituted consonants (or covert contrast). Two groups of children who had participated in a larger study that examined the influence of speech production abilities on speech perception scores of children with CI (Gonzalez, 2013) provided the speech stimuli for this investigation. The experimental group included nine congenitally deafened children with CI, ranging in age from 2;11 to 6;4 years (M=4;9), who were implanted by 3 years of age, had at least 12 months of device experience, and only used an oral mode of communication. These children were matched to typically developing children by articulation ability and gender. Recordings of the verbal responses on the OlimSpac were obtained from the Gonzalez (2013) study. Thirty-three graduate students in speech-language pathology rated the phonetic accuracy of /t/ and the phonemes that were found to be most often substituted for it, /d/ and /ʧ/ on a 7 point equal-appearing interval scale. A three-way ANOVA was performed to determine the differences in perceived consonant accuracy across: group, transcription category, and phoneme substitution. The significant interaction between group and transcription category was of particular interest. Results indicated that children with CIs did not show an unusually delayed development of /t/. When a confusion matrix was generated to depict overall OlimSpac performance, the NH group was noted to outperform the CI group across all phonemes. This would suggest that /t/ was not uniquely poorer in the CI group, but instead these children evidenced poorer phoneme accuracy in general. Finally, group differences also were apparent in substitutions of [t] for target /d/ and /ʧ/ productions (i.e., covert contrast). The clinical applications are described.

The relationship between feeding development and early speech production has received increasing interest over the past 30 years. If a relationship between the motor control systems for feeding and communication is present, it could have implications for the early identification of communication deficits in children. Theoretical support exists for a relationship between the feeding and speech motor systems based on evolutionary theory (Blanchard, 1963), and anatomical similarities in oral motor function (Morris, 1985, 1990, 1991, 1998). However, the existence of a causal relationship between early feeding and communication development remains uncertain due to a lack of empirical research. A model proposed by Carpendale and Lewis (2004) encompasses the triadic interaction between the environment, maternal factors, and infant factors, which can influence both feeding and communication development. Clinical feeding assessments typically employed by clinicians and researchers are most often carried out with observational checklists. Data reflecting the theoretical foundation, validity, and reliability for these tools are limited. Observation tools assess specific aspects of feeding and oral motor control from a modular perspective, without regard for the infant’s total feeding system. Rogers and Arvedson (2005) highlighted the need for a single standardised assessment tool to assess infant feeding descriptively and objectively. The primary aim of the project was to determine whether the same motor control mechanisms are utilised for oral feeding and communication. The first stage of the study involved the development of a theoretically informed assessment protocols to document systematically the development of feeding skills from birth, the Feeding Assessment Observation (FAO) and the Feeding Assessment Questionnaire (FAQ). / The assessment protocol was piloted on 10 term and 10 preterm infants at 1 to 2 weeks, 4, 8 and 12 months corrected age (CA) for preterm infants and chronological age for term infants. The second stage of the project examined the progression of feeding and communication development in a group of term and preterm infants over a 12 month period. The progression of 8 preterm and 7 term infants was observed at 1-2 weeks, 4, 8 and 12 months CA and chronological age for term infants. The mean gestational age for preterm infants was 30 weeks, 6 days (SD = 6.8 days), and term infants was 39 weeks, 5 days (SD = 9.4 days). Assessment of the infants’ feeding and communication skills, environmental and maternal influences was conducted using the initial questionnaire, Feeding Assessment Observation (FAO), Feeding Assessment Questionnaire (FAQ), Home Screening Questionnaire (HSQ), Receptive Expressive Emergent Language Scale, second edition (REEL-2), and the infant-toddler checklist of the Communication and Symbolic Behavior Scales Developmental Profile (CSBS-DP), to determine the nature and impact of environmental and social factors on feeding and/or communication development. Preliminary reliability testing of the FAO was conducted. Sixty seven percent (10/15) of observation items achieved greater than 90% inter-observer agreement. There was no significant difference in feeding and communication development between term and preterm infants. The negative linear trend for the development of feeding efficiency on liquids for infants was opposed to the positive linear trend for communication development. Infant feeding efficiency on solids showed parallel positive linear developmental trends with communication development. / Comprehensive data were collected on influencing factors from infant, maternal and environmental domains during the initial assessment, and the 4, 8 and 12 month CA developmental reviews. The data revealed significant differences between the term and preterm groups for infant and environmental factors, but no significant differences were found for maternal influences. The study provided some support for the hypothesis of integrative motor control and co-development of feeding and communication. The prediction that infant, maternal, and environmental factors would significantly influence feeding and communication development was not supported. In addition, there was no difference in the impact of influencing factors for the term and preterm groups. The feeding and communication skills of preterm infants developed at corrected age levels, and were not significantly slower than term infants. Furthermore, predicted delays in feeding development were not associated with concomitant delays in communication development for term and preterm infants. Further investigation of the subsequent communication development of infants with definitive feeding difficulties and with a larger sample is suggested.

As ultrasound imaging gains popularity in speech research, an important question to address is the reliability of the measures taken from these images. This study examines the reliability of hand measures of ultrasound data collected by graduate student researchers in the University of South Florida's speech science lab. Speech production data from Ultrasound analysis of velar fronting (Wodzinski, 2004) and Ultrasound study of errors in speech production (Frisch, 2003) were used to obtain inter-rater reliability measures. This study compares the raters choice of video frame depicting alveolar or velar closure image, anterior and posterior points of closure, tongue blade and velar angle measurements, as well as a measurement of the tongue dorsum distance from the ultrasound probe.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

Dell (1986) presented a spreading activation model which accounted for a number of early speech error results, including the relative proportions of anticipations, perseverations and exchanges found in speech error corpora, the lexical bias effect, the phonological similarity effect, and the effect of speech rate on error rate. This model has had an immense influence on the past 20 years of research into word production, with the original paper being cited over 1,000 times. Many studies have questioned how activation should flow between words and phonemes in this model. This thesis aimed to clarify what current speech error evidence tells us about how activation flows between phonemes and subphonemic representations, like features. Does activation cascade from phonemes to features, and does it feed back? The work presented here extends previous modelling investigations in two ways. Firstly, whereas previous modelling research has tended to evaluate model behaviour using arbitrarily chosen parameter settings, we illuminate the influence of the parameters on model behaviour and propose methods to draw general conclusions about model behaviour from large numbers of simulations at orthogonally varied parameter settings. Secondly, we extend the scope of the simulations to consider output at a subphonemic level, modelling recent data acquired via acoustic and articulatory measurements, such as voicing onset time (VOT), electropalatography (EPG) and ultrasound, alongside older transcribed speech error data. Throughout the thesis, we consider whether parameter settings which lead the model to capture individual results also permit other results to be accounted for and do not cause otherwise implausible behaviour. Through manipulating parameter settings in Dell's (1986) original model, we find that increasing the number of steps before selection generally does not decrease the error rate, but rather increases it, contrary to results reported by Dell (1986). This calls into question the claim that an increase in steps before selection provides a good model of a slower speech rate. We also demonstrate that the model captures the negative correlation reported by Dell, Burger, and Svec (1997) between error rate and the ratio of anticipations to perseverations, and further predicts that there should be a negative correlation between this ratio and the proportion of errors which are non-contextual. However, our results show that no parameter setting allows the model to generate enough exchanges to match even minimum estimates from a reanalysis of multiple speech error corpus reports, without falling foul of other constraints; in particular, limits on the overall number of errors generated. We suggest that the exchange completion triggering mechanism proposed by Dell (1986) is not strong enough, and that current corpus evidence provides little support for his account of word sequencing. Focusing on single word production therefore, the second part of the thesis investigates behaviour of models with output at a subphonemic level. We find that, provided sufficient contextual errors occur at the featural level, a model in which only the identity of the selected phoneme is conveyed to the featural level can account for: (i) the phonological similarity effect found in transcribed records of speech errors (whereas in models with output at the phoneme level, feedback from features to phonemes is required); (ii) detectable influences of intended phonemes in VOT measurements of unintended phonemes, as well as the effect of error outcome lexicality on these results ( findings presented in support of cascading from phonemes by Goldrick & Blumstein, 2006); and (iii) increased similarity of EPG measurements of articulations to reference measurements of competing articulations when production of the competing onset would result in a word (McMillan, Corley, & Lickley, 2009). Initial results appear to con firm however that, in contrast, phonological similarity effects on the relationship of articulatory and acoustic measurements of productions to reference measurements (McMillan, 2008) can only be accounted for in an architecture with feedback from features to phonemes. To strengthen conclusions about articulatory evidence of lexical bias and phonological similarity effects, future work needs to consider the extremely strong effects of frequency observed in these simulations. The results presented in this thesis contribute to a greater comprehension of the behaviour of Dell's (1986) influential model, and further demonstrate that the model can be extended to account for new instrumental evidence, whilst clarifying the constraints on activation flow between phonemes and features which this new evidence imposes.

The study aims to describe and to explain some temporal aspects of the rhythmic structure of Swedish, and to compare Swedish, Spanish, and Finnish, characterized as rhythmically different languages. The temporal effects of some manipulations believed to have consequences for rhythm were studied in a series of experiments based on sets of Swedish sentences. These manipulations included the length of stress groups - the number of unstressed syllables between stressed ones - and their structural properties. Also the length of the surrounding stress group was varied, as well as speech rate. The results indicated the presence of several interacting factors. First, there was an inverse relation between the length of the phrase and the duration of the stress group: phrase-lenqth adjustments. Ihe effects were similar to those obtained when speech rate was independently varied. Secondly, adjacent stress groups were adjusted so that differences of duration were counteracted: stress-qroup adjustments. In addition, in longer stress groups rhythmic alternation between unstressed syllables occurred. Finally, there was an interplay between rhythm and language structure. This was evident from the stability of the temporal manifestations of the quantity distinction and the distinction between stressed and unstressed syllables irrespective of the experimental manipulations. The results were interpreted in terms of a process model of speech rhythm, the generality of which was considered in the cross-language comparisons. The presence of similar temporal effects in all three languages was taken to support assumptions of language-independent processing constraints. Deviations from the general pattern were explainable in terms of differences of language structure and adjustments to preserve important structural properties, especially quantity relations. / <p>Diss. Umeå : Umeå universitet, 1985</p> / digitalisering@umu

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