Speech vocoding for laboratory phonology

Using phonological speech vocoding, we propose a platform for exploring relations between phonology and speech processing, and in broader terms, for exploring relations between the abstract and physical structures of a speech signal. Our goal is to make a step towards bridging phonology and speech processing and to contribute to the program of Laboratory Phonology. We show three application examples for laboratory phonology: compositional phonological speech modelling, a comparison of phonological systems and an experimental phonological parametric text-to-speech (TTS) system. The featural representations of the following three phonological systems are considered in this work: (i) Government Phonology (GP), (ii) the Sound Pattern of English (SPE), and (iii) the extended SPE (eSPE). Comparing GP- and eSPE-based vocoded speech, we conclude that the latter achieves slightly better results than the former. However, GP - the most compact phonological speech representation - performs comparably to the systems with a higher number of phonological features. The parametric TTS based on phonological speech representation, and trained from an unlabelled audiobook in an unsupervised manner, achieves intelligibility of 85% of the state-of-the-art parametric speech synthesis. We envision that the presented approach paves the way for researchers in both fields to form meaningful hypotheses that are explicitly testable using the concepts developed and exemplified in this paper. On the one hand, laboratory phonologists might test the applied concepts of their theoretical models, and on the other hand, the speech processing community may utilize the concepts developed for the theoretical phonological models for improvements of the current state-of-the-art applications

The relationship of phonological ability, speech perception, and auditory perception in adults with dyslexia

This study investigated whether auditory, speech perception and phonological skills are tightly interrelated or independently contributing to reading. We assessed each of these three skills in 36 adults with a past diagnosis of dyslexia and 54 matched normal reading adults. Phonological skills were tested by the typical threefold tasks, i.e. rapid automatic naming, verbal short term memory and phonological awareness. Dynamic auditory processing skills were assessed by means of a frequency modulation (FM) and an amplitude rise time (RT); an intensity discrimination task (ID) was included as a non-dynamic control task. Speech perception was assessed by means of sentences and words in noise tasks. Group analysis revealed significant group differences in auditory tasks (i.e. RT and ID) and in phonological processing measures, yet no differences were found for speech perception. In addition, performance on RT discrimination correlated with reading but this relation was mediated by phonological processing and not by speech in noise. Finally, inspection of the individual scores revealed that the dyslexic readers showed an increased proportion of deviant subjects on the slow-dynamic auditory and phonological tasks, yet each individual dyslexic reader does not display a clear pattern of deficiencies across the levels of processing skills. Although our results support phonological and slow-rate dynamic auditory deficits which relate to literacy, they suggest that at the individual level, problems in reading and writing cannot be explained by the cascading auditory theory. Instead, dyslexic adults seem to vary considerably in the extent to which each of the auditory and phonological factors are expressed and interact with environmental and higher-order cognitive influences

Lexicality and frequency in specific language impairment: accuracy and error data from two nonword repetition tests

Purpose: Deficits in phonological working memory and deficits in phonological processing have both been considered potential explanatory factors in Specific Language Impairment (SLI). Manipulations of the lexicality and phonotactic frequency of nonwords enable contrasting predictions to be derived from these hypotheses. Method: 18 typically developing (TD) children and 18 children with SLI completed an assessment battery that included tests of language ability, non-verbal intelligence, and two nonword repetition tests that varied in lexicality and frequency. Results: Repetition accuracy showed that children with SLI were unimpaired for short and simple high lexicality nonwords, whereas clear impairments were shown for all low lexicality nonwords. For low lexicality nonwords, greater repetition accuracy was seen for nonwords constructed from high over low frequency phoneme sequences. Children with SLI made the same proportion of errors that substituted a nonsense syllable for a lexical item as TD children, and this was stable across nonword length. Conclusions: The data show support for a phonological processing deficit in children with SLI, where long-term lexical and sub-lexical phonological knowledge mediate the interpretation of nonwords. However, the data also suggest that while phonological processing may provide a key explanation of SLI, a full account is likely to be multi-faceted

Reading-related skills of kindergarteners from diverse linguistic backgrounds

This study examined whether measures used to identify children at risk for reading failure are appropriate for children from different language backgrounds. Tasks assessing literacy and phonological and language processing at the beginning and end of kindergarten were administered to 540 native English speakers (NS), 59 bilingual children (BL), and 60 children whose initial exposure to English was when they began school (ESL). Although the BL and ESL children performed more poorly than the NS children on most measures of phonological and linguistic processing, the acquisition of basic literacy skills for children with different language backgrounds developed in a similar manner. Furthermore, planned contrasts between the language groups did not explain the variance in the children’s literacy performance in May. Instead, alphabetic knowledge and phonological processing were important contributors to early reading skill. Therefore, children learning English may acquire literacy skills in English in a similar manner to NS children, although their alphabetic knowledge may precede and facilitate the acquisition of phonological awareness in English

A longitudinal study of phonological processing skills and reading in bilingual children

French/English bilingual children (N=40) in French language schools participated in an 8-month longitudinal study of the relation between phonological processing skills and reading in French and English. Participants were administered measures of phonological awareness, working memory, naming speed, and reading in both languages. The results of the concurrent analyses show that phonological awareness skills in both French and English were uniquely predictive of reading performance in both languages after accounting for the influences of cognitive ability, reading ability, working memory, and naming speed. These findings support the hypothesis that phonological awareness is strongly related to beginning word reading skill in an alphabetic orthography. The results of the longitudinal analyses also suggest that orthographic depth influences phonological factors related to reading

Ageing makes us dyslexic

Background: The effects of typical ageing on spoken language are well known: word production is disproportionately affected while syntactic processing is relatively well preserved. Little is known, however, about how ageing affects reading.Aims: What effect does ageing have on written language processing? In particular, how does it affect our ability to read words? How does it affect phonological awareness (our ability to manipulate the sounds of our language)?Methods & Procedures: We tested 14 people with Parkinson's disease (PD), 14 typically ageing adults (TAA), and 14 healthy younger adults on a range of background neuropsychological tests and tests of phonological awareness. We then carried out an oral naming experiment where we manipulated consistency, and a nonword repetition task where we manipulated the word-likeness of the nonwords.Outcomes & Results: We find that normal ageing causes individuals to become mildly phonologically dyslexic in that people have difficulty pronouncing nonwords. People with Parkinson's disease perform particularly poorly on language tasks involving oral naming and metalinguistic processing. We also find that ageing causes difficulty in repeating nonwords. We show that these problems are associated with a more general difficulty in processing phonological information, supporting the idea that language difficulties, including poorer reading in older age, can result from a general phonological deficit.Conclusions: We suggest that neurally this age-induced dyslexia is associated with frontal deterioration (and perhaps deterioration in other regions) and cognitively to the loss of executive processes that enable us to manipulate spoken and written language. We discuss implications for therapy and treatment

Neuronal activation for semantically reversible sentences

Semantically reversible sentences are prone to misinterpretation and take longer for typically developing children and adults to comprehend; they are also particularly problematic for those with language difficulties such as aphasia or Specific Language Impairment. In our study, we used fMRI to compare the processing of semantically reversible and nonreversible sentences in 41 healthy participants to identify how semantic reversibility influences neuronal activation. By including several linguistic and nonlinguistic conditions within our paradigm, we were also able to test whether the processing of semantically reversible sentences places additional load on sentence-specific processing, such as syntactic processing and syntactic-semantic integration, or on phonological working memory. Our results identified increased activation for reversible sentences in a region on the left temporal–parietal boundary, which was also activated when the same group of participants carried out an articulation task which involved saying “one, three” repeatedly. We conclude that the processing of semantically reversible sentences places additional demands on the subarticulation component of phonological working memory

Theories of developmental dyslexia: Insights from a multiple case study of dyslexic adults

A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: the phonological, the magnocellular (auditory and visual) and the cerebellar theories. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and cerebellar tests. Individual data reveal that all 16 dyslexics suffer from a phonological deficit, 10 from an auditory deficit, 4 from a motor deficit, and 2 from a visual magnocellular deficit. Results suggest that a phonological deficit can appear in the absence of any other sensory or motor disorder, and is sufficient to cause a literacy impairment, as demonstrated by 5 of the dyslexics. Auditory disorders, when present, aggravate the phonological deficit, hence the literacy impairment. However, auditory deficits cannot be characterised simply as rapid auditory processing problems, as would be predicted by the magnocellular theory. Nor are they restricted to speech. Contrary to the cerebellar theory, we find little support for the notion that motor impairments, when found, have a cerebellar origin, or reflect an automaticity deficit. Overall, the present data support the phonological theory of dyslexia, while acknowledging the presence of additional sensory and motor disorders in certain individuals

Phonology is Fundamental in Skilled Reading

There is controversy about the importance of phonology in skilled reading. Event-related potential (ERP) evidence from the initial moments of visual word recognition indicates that processing sub-lexical phonology is fundamental to skilled reading. The early timecourse of this phonological activation explains the predictive power of phonological awareness for early reading development, affirms the importance of phonological processing in learning to read, and illuminates the persistent challenges of dyslexia

Predictors of exception word and nonword reading in dyslexic children: the severity hypothesis

The classification of dyslexic children into discrete subtypes yields a poor description of the dyslexic population at large. Multiple regression methods were used to examine continuous variation in component reading subskills (nonword and exception word reading) and their underlying cognitive skills within a group of 59 9-15 year-old dyslexic children. Two measures of phonological skills contributed unique variance to nonword reading: phonological processing and verbal short-term memory skills. In contrast, the only unique predictor of exception word reading was reading experience. The results are discussed within a connectionist framework that views the decoding deficit in dyslexia as stemming from poorly specified phonological representations. The extent of the nonword reading deficit is determined by the severity of the underlying phonological impairment. In contrast, exception word reading is influenced more by print exposure