Across three experiments, the current study explored how accented speech and coarticulation impact how bilingual listeners comprehend code-switches in speech. Eye-tracking methodology was used to compare responses to single-language and code-switched sentences. Experiment 1 observed how accented speech influenced the costs involved in…

Purpose: The /[voiced alveolar approximant]/ productions of young children acquiring American English are highly variable and often inaccurate, with [w] as the most common substitution error. One acoustic indicator of the goodness of children's /[voiced alveolar approximant]/ productions is the difference between the frequency of the second…

Background: Dementia is a cognitive decline that leads to the progressive deterioration of an individual's ability to perform daily activities independently. As a result, a considerable amount of time and resources are spent on caretaking. Early detection of dementia can significantly reduce the effort and resources needed for caretaking. Aims:…

Individual speakers' speech patterns differ from one another, despite presumably similar language input. What are the sources of this individual variability? In this dissertation, I explore sources of individual differences in pronunciation of coronal obstruents (/s/, /t[superscript h]/, /c[superscript h]/, /c/) at the ends of nouns in Korean.…

Purpose: This meta-analysis study aimed to determine the optimal level of talker variability in training to maximize second-language speech learning. Method: We conducted a systematic search for studies comparing different levels of talker variability in nonnative speech training, published through July 2024. Two independent reviewers screened…

This case report describes a young child with inconsistent phonological disorder (IPD). The child presented with unintelligible speech. She made limited progress on individual speech production goals targeting phonological patterns over 4 years, remaining unintelligible. The child was diagnosed with IPD following an inconsistency assessment and…

This study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers' spontaneous speech addressed to their 11- to 24-month-old infants (infant-directed speech, IDS) and an adult experimenter (adult-directed speech, ADS). The data were collected between 2016 and 2018 in Aarhus, Denmark. Prosodic properties of Danish…

Purpose: Phonologically complex targets (e.g., [pl-]) are understood to facilitate widespread gains following speech sound intervention, and yet, available research largely features word-"initial" clusters. The present study investigates intervention effects following treatment of complex clusters presented in word-"final"…

There is a long-standing debate in the literature about the benefits that acoustic components of Infant Directed Speech (IDS) might have for infants' language acquisition. One of the highly contested features is vowel space expansion, which refers to the enlargement of the acoustic space between the corner vowels /i, u, a/ in IDS compared to Adult…

Research on the acoustic characteristics of Infant Directed Speech (IDS) in North American English indicates that it is generally higher-pitched than Adult Directed Speech (ADS) and has unique prosodic characteristics, which is commonly found across many spoken languages. However, very little research has addressed another important aspect of…

Background: Parkinson's disease (PD) has an impact on speech production, manifesting in various ways including alterations in voice quality, challenges in articulating sounds and a decrease in speech rate. Numerous investigations have been conducted to ascertain the oral-diadochokinesis (O-DDK) rate in individuals with PD. However, the existing…

Purpose: According to the interpersonal synergy model of spoken dialogue, interlocutors modify their communicative behaviors to meet the contextual demands of a given conversation. Although a growing body of research supports this postulation for linguistic behaviors (e.g., semantics, syntax), little is understood about how this model applies to…

Background: Previous research has found that high-frequency energy of speech signals decreased while wearing face masks. However, no study has examined the specific spectral characteristics of fricative consonants and vowels and the perception of clarity of speech in mask wearing. Aims: To investigate acoustic-phonetic characteristics of fricative…

Purpose: The human voice changes with the progression of neurological disease and the onset of diseases that affect articulators, often decreasing the effectiveness of communication. These changes can be objectively measured using signal processing techniques that extract acoustic features. When measuring acoustic features, there are often several…

Background: Within cohorts of children with autism spectrum disorder (ASD) there is considerable variation in terms of language ability. In the past, it was believed that children with ASD either had delayed articulation and phonology skills or excelled in those areas compared to other language domains. Very little is known about speech sound…