Several fundamental questions about speech perception concern how listeners understand spoken language despite considerable variability in speech sounds across different contexts (the problem of lack of invariance in speech). This contextual variability is caused by several factors, including differences between individual talkers' voices, variation in speaking rate, and effects of coarticulatory context. A number of models have been proposed to describe how the speech system handles differences across contexts. Critically, these models make different predictions about (1) whether contextual variability is handled at the level of acoustic cue encoding or categorization, (2) whether it is driven by feedback from category-level processes or interactions between cues, and (3) whether listeners discard fine-grained acoustic information to compensate for contextual variability. Separating the effects of cue- and category-level processing has been difficult because behavioral measures tap processes that occur well after initial cue encoding and are influenced by task demands and linguistic information. Recently, we have used the event-related brain potential (ERP) technique to examine cue encoding and online categorization. Specifically, we have looked at differences in the auditory N1 as a measure of acoustic cue encoding and the P3 as a measure of categorization. This allows us to examine multiple levels of processing during speech perception and can provide a useful tool for studying effects of contextual variability. Here, I apply this approach to determine the point in processing at which context has an effect on speech perception and to examine whether acoustic cues are encoded continuously. Several types of contextual variability (talker gender, speaking rate, and coarticulation), as well as several acoustic cues (voice onset time, formant frequencies, and bandwidths), are examined in a series of experiments. The results suggest that (1) at early stages of speech processing, listeners encode continuous differences in acoustic cues, independent of phonological categories; (2) at post-perceptual stages, fine-grained acoustic information is preserved; and (3) there is preliminary evidence that listeners encode cues relative to context via feedback from categories. These results are discussed in relation to proposed models of speech perception and sources of contextual variability.

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This thesis provides a literature review on various topics related to the aims of the research project. In the process of sketching the rationale of this study, the language-in-education policy (LiEP) of South Africa is examined. The reasons why this policy is not successful, is discussed. Emanating from this discussion, the low literacy scores amongst young learners in South Africa are described and possible reasons for this occurrence are cited (Howie, Van Staden, Tshele, Dowse, & Zimmerman, 2012). The hypothesis that perceptual and articulation training of the vowels of English would enhance young English second language (Setswana first language-speaking) learners? awareness of English vowels, is posited and defended by referring to previous research (Moats, 2007; Trehearne, 2011; Seeff-Gabriel, 2003). In addition, it is stated that increased knowledge of the vowel system of English will improve English second language (EL2) learners? literacy skills (Moats, 2007). In order to explain and discuss the results of the investigations into the literacy skills of the EL2 learners participating in this study, the notions of literacy acquisition, phonological awareness skills, and language acquisition and language learning are examined. The main aim of this study is to assess the effects of intervention on the auditory perception and articulatory skills of English second language-speaking (EL2) (Setswana L1-speaking) learners in Grade 3, in the production of the monophthongs and diphthongs of the standard variety of South African English, namely White South African English (WSAfE) (Bekker, 2009). The effects are determined by acoustically comparing the vowel spaces of the participants before and after intervention. Therefore, a discussion of acoustic concepts such as the vowel space and the parameters thereof are provided. In addition, the vowels of WSAfE, those of Black South African English (BSAE), and the vowels of Setswana are discussed and compared according to their acoustic features. The results of this quasi-experimental, comparative study indicate that the vowel spaces of the EL1 and EL2 participants differ markedly before intervention, especially when comparing those of the short and long monophthongs of English. After intervention, the vowel spaces of especially the Experimental group are seen to approximate those of the EL1 participants in the Norm group. Interesting findings concerning the central schwa vowels and the diphthongs were made. These indicate that young EL2 (Setswana L1-speaking) learners do not use BSAE, but use a new? variety of English that is closer to WSAfE (Mesthrie, 2008). Pertaining to the measurable sub-aims of this study, the phonological awareness skills and literacy skills of the participants are assessed and compared, before and after intervention. The improvement of the phonological awareness skills and literacy skills of the Experimental group, as well as the changes in the vowel spaces that are noted for this group, prove the hypothesis that intervention in the form of additional input concerning the English vowels will enhance second language learners? perception and articulation. This strengthens the opinion that second language learners need quality teaching of the sound system of the language of learning and teaching. / Thesis (DPhil)--University of Pretoria, 2016. / African Languages / DPhil / Unrestricted

Nonword repetition tasks were originally devised to assess the efficiency of the phonological loop (Baddeley & Hitch, 1974), a component of the working memory system, where verbal information is temporarily stored and translated to support activities like phonological processing during early word-recognition (Snowling, 1981; Wagner et al., 2003), speech production (McCarthy & Warrington, 1984), and articulation (Watkins, Dronkers, & Vargha-Khadem, 2002; Yoss & Darley, 1974). From a practical perspective, there is a significant need for a systematically-designed Spanish nonword repetition measure that is equivalent to currently-available English measures. For this study, a database of nonwords that considered phonotactic and phonological properties of Spanish was devised. In a preliminary study, Spanish-speaking adults provided wordlikeness judgments about a large set of candidate nonwords. A subset of the rated nonwords was used in the development of a Spanish nonword repetition measure. The aim of the main experiment was to explore the contributions of participant factors (age, gender, and vocabulary knowledge) and item factors (word length, stress pattern, and wordlikeness) to Spanish repetition performance in this group of Spanish speaking, English language learning children. From a theoretical perspective, this investigation allowed a first observation of how experience with listening to and producing Spanish words influences the acquisition of Spanish-specific phonological patterns. A total of 68 children, ages four to six years with varying degrees of Spanish language knowledge participated in this study. Results revealed significant age and word length effects. However, stress pattern did not exert significant effects on repetition performance, which is not completely consistent with previous literature. That is, participants repeated nonwords from both the more frequent and the less frequent stress pattern with similar accuracy. Wordlikeness, a previously uninvestigated variable in nonword repetition was found to affect repetition accuracy. For all participants, nonwords rated as high in wordlikeness were more accurately repeated than were nonwords with low wordlikeness ratings. Findings of the study are discussed in terms of how they relate to working memory and usage-based models of phonological learning. Finally, the clinical relevance of nonword repetition in the assessment of coarse- and fine-grained mappings of phonological knowledge is suggested.

Speech development in autism spectrum disorder (ASD) has rarely been studied, yet residual speech sound errors are over 30 times more common in children with ASD than in the general population. Two main theories could explain this. The Social Feedback Loop proposes that toddlers with ASD vocalize less often and so have fewer opportunities to benefit from adult feedback. Thus, fewer vocalizations and perceptible differences in those vocalizations should be found in toddlers with ASD. The Speech Attunement Framework proposes that while toddlers with ASD “tune in” to their native languages well enough to acquire language normally, they lack the ability to “tune up” their articulation to the same level of precision as typically-developing children. Thus, differences in the vocalizations of toddlers with ASD may be perceptible or not, and should exist irrespective of differences in vocalization rate. This study longitudinally examines vocalization rate, consonant inventory size, and voice-onset time (VOT) in syllable-initial bilabial stops using 30-minute speech samples from toddlers in three groups: those at low risk for ASD (LRC), those at high risk for ASD with ASD themselves (HRA+), and those at high risk for ASD without ASD (HRA ) . Transient delays in consonant development were found in both HRA- and HRA+, but only HRA+ toddlers vocalized less often. Further, the relationship between vocalization rate and consonant inventory was significantly different from LRC only for HRA-. VOT development was similar across groups, except that fewer HRA+ 36-month-olds produced distinct /b/ and /p/ populations, as measured by t-test and by Cohen’s d ≥ 0.8 between mean VOTs in the two populations of stops. Results support the Speech Attunement Framework. Consonant acquisition delays are not related to differences in vocalization rate and are not found only in toddlers who develop ASD. The finding of sub-perceptual acoustic differences in stop production in toddlers who develop ASD, with no accompanying differences in production rate, also supports the Speech Attunement Framework. This suggests that the Social Feedback Loop is not diminished in ASD by lower vocalization rate, but that toddlers with ASD may have diminished ability to monitor their own speech.

Att inneha fonologisk medvetenhet är grunden i att utveckla läsning. Fonologisk medvetenhet innebär förmågan att urskilja de ljud som finns representerade i språkets ljudsystem. Fonologisk medvetenhet har en underkategori som kallas fonemisk medvetenhet. Det innebär att barnet kan urskilja språkljud eller fonem i ett ord. För lärare i årskurs F–3 är det intressant att ta del av vilka undervisningsmetoder som lärare i förskoleklass använder för att främja fonologisk medvetenhet. Studien har en kognitiv utgångspunkt och resultaten analyseras efter modellen Phonological awareness intervention beyond the basics (Schuele & Boudreau, 2008). Studiens insamlade material består av fyra intervjuer med förskoleklasslärare. Intervjusvaren har tematiserats under rubrikerna undervisning, möjligheter och utmaningar. Resultatet visar att lärarna använder undervisningsmetoderna FonoMix och Läsresan, men komplettera med Bornholmsmodellen. Lärarna använder konkret material som stöd för att hjälpa eleverna att lära in språkljuden. Lärarna anser att deras fonologiska undervisning är positiv för nyanlända elever och elever med svårigheter att uttala språkljud. Slutsatsen är att undervisningsmetoderna ger ett bra underlag för undervisning inriktad på fonologisk medvetenhet. Som lärare bör man dock vara uppmärksam på att ingen dessa undervisningsmetoder är fonologiskt komplett, utan bör kombineras med andra metoder för att få en mer omfattande fonologisk undervisning.

There are a number of clinical options available for speech-language pathologists to choose from to analyze a child's phonological system, select treatment targets, and design intervention. Frequently, each of these areas of clinical options is viewed independently of one another or approached within an eclectic framework. In this article, an integrated and systemic approach is presented which assumes that a dynamic interaction exists among assessment, target selection, and intervention. Systemic Phonological Assessment of Child Speech, the distance metric approach to target selection, and the multiple oppositions treatment approach are described, with examples provided for each component. Finally, a case study is presented that examines the systemic approach of multiple oppositions relative to the approach of minimal pairs.

This study aimed to describe the phonological development of Setswana-speaking children between the ages of 2;0 and 6;5 years. The study objectives were to: 1) describe the acquisition of four aspects of phonology in these children, namely vowels, consonants, lexical tone and phonological processes; 2) contrast Setswana phonological development in monolingual vs multilingual children; and 3) contrast typical vs atypical Setswana speech acquisition and determine the occurrence and nature of speech sound disorders in children acquiring Setswana. The participant group comprised 81 children from the North-West Province of South Africa. All children were attending preschool and were acquiring one of two varieties of Setswana investigated in this study, namely Sekwêna and Setlhaping. Sixty-five participants were acquiring Sekwêna and were recruited from Hebron, and the remaining 16 participants were acquiring Setlhaping and were recruited from Dry-Harts village. The study used a cross-sectional design to detail the stages of phonological development in children aged 2;0–6;5 years. For each of the varieties studied, participants were assigned to groups of six-month age bands (e.g. 2;6– 2;11 years). Findings add to data from a preliminary pilot study on the acquisition of Setswana segmental phonology (Mahura, 2014; Mahura & Pascoe, 2020). Prior to obtaining speech samples from Setswanaspeaking children, revisions were made to the assessment developed in the pilot study. This was done by addressing a number of limitations which had been documented following its use, including ensuring that all consonant phonemes were targeted in the initial word and penultimate syllable positions, as well as including syllabic consonants in these word positions. The picture stimuli were also changed, and an expert panel assessed the revised word list to ensure that all words were linguistically and culturally appropriate. Participants' speech was transcribed online using IPA symbols and audio recorded for later re-transcription to ensure reliability. The findings indicate that children acquiring Setswana have a full set of vowels in their phonetic inventories as early as 2;6 years, and possibly earlier. A large number of consonant phonemes occurring in the Setswana phonological system had either been acquired or mastered by 2;6–2;11 years. This was seen word-initially and in the penultimate syllable position, with only three phonemes still to be acquired at this age word-initially: only two phonemes with rounding, velar plosive /kʷʼ/ and alveolar nasal /nʷ/, were still emerging at 2;6–2;11 years and seen to be acquired at 3;0–3;5 years in the initial word position and voiced palato-alveolar affricate /ʤ/ was absent at 2;6–2;11 years. This phoneme was, however, seen to emerge in the 3;0–3;5-year group. Heterorganic compounds in the initial word position mainly consisted of /fj/ and were only seen in the speech of children who speak the Sekwêna variety. Conclusions on the age at which heterorganic compound /fj/ is acquired could not be made as it was not used by all children acquiring the Sekwêna variety, but instead observed in the speech of several participants across the different age bands. Although consonant clusters were not included in the consonant phonemes elicited as part of this study, they were noted in the inventories of children across the different age groups. A clear reduction in the occurrence of phonological processes was seen across age group, a pattern of development that can be expected in typically-developing children. Some of the phonological processes seen in Setswana-speaking children included assimilation (eliminated after 6;5 years), fronting (eliminated at 3;6 yeas), and stopping (eliminated at 4;0 years). Correct use of lexical tone was observed as early as 2;6–2;11 years. Furthermore, the speech sound skills of bi/multilingual children were found to be comparable to their monolingual peers, and sometimes slightly more advanced. Findings are related to existing theoretical frameworks used to describe speech sound acquisition. While the findings from this study are not yet generalisable to all Setswana-speaking children, they indicate that theoretical frameworks such as Stackhouse and Wells' (1997) psycholinguistic approach and Dodd's (1995; 2005) diagnostic framework can be applied to Setswana. Language specific differences that should be taken into account are presented. This data adds to knowledge on speech sound acquisition in Setswana-speaking children, urgently needed for the early assessment and identification of children with speech difficulties, which has been lacking to date. When speech difficulties are identified and addressed early, children's academic, psychosocial and life outcomes can be improved, but Setswana-speaking children are often not well served by speech and language therapists in South Africa due to a lack of relevant information and resources. This study set out to redress this situation. Lines for future research include using a larger sample of participants to allow data to be more generalisable, developing assessments for speech input processing as well as production and considering aspects of tone more comprehensively.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19889号 / 医博第4138号 / 新制||医||1016(附属図書館) / 32966 / 京都大学大学院医学研究科医学専攻 / (主査)教授 古川 壽亮, 教授 髙橋 良輔, 教授 富樫 かおり / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM