Purpose: Talkers adapt their speech according to the demands of their listeners and the communicative context, enhancing the properties of the signal (pitch, intensity) and/or properties of the code (enhancement of phonemic contrasts). This study asked how mothers adapt their child-directed speech (CDS) in ways that might serve the immediate goals…

Before they even talk, infants become sensitive to the speech sounds of their native language and recognize the auditory form of an increasing number of words. Traditionally, these early perceptual changes are attributed to an emerging knowledge of linguistic categories such as phonemes or words. However, there is growing skepticism surrounding…

Code-switching (switching between languages) is a common linguistic behavior in bilingual speech directed to infants and children. In adult-directed speech (ADS), acoustic-phonetic properties of one language may transfer to the other language close to a code-switch point; for example, English stop consonants may be more Spanish-like near a switch.…

This dissertation explores the relationship between quantitative phonetic measurements and listener identification of accents of English, focusing on phonetic distance and its perceptual correlates across various English accent varieties. The Levenshtein distance (LD) measure, which quantifies string similarity by calculating the minimum cost of…

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…

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…

Purpose: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects bulbar functions including speech and voice. Voice onset time (VOT) was examined in speakers with ALS in early and late stages to explore the coordination of the articulatory and phonatory systems during speech production. Method: VOT was measured in nonword…

Purpose: This study investigated vowel and sibilant productions in noise to determine whether responses to noise (a) are sensitive to the spectral characteristics of the noise signal and (b) are modulated by the contribution of vowel or sibilant contrasts to word discrimination. Method: Vowel and sibilant productions were elicited during serial…

This study investigates whether listeners' cue weighting predicts their real-time use of asynchronous acoustic information in spoken word recognition at both group and individual levels. By focusing on the time course of cue integration, we seek to distinguish between two theoretical views: the "associated" view (cue weighting is linked…

In the first year of life, infants' speech perception becomes attuned to the sounds of their native language. This process of early phonetic learning has traditionally been framed as phonetic category acquisition. However, recent studies have hypothesized that the attunement may instead reflect a perceptual space learning process that does not…

This sociophonetic study examines affricate variation through a continuous lens using diachronic data from Caracas Spanish. We investigate the relationship between frication and occlusion period duration in affricate segments across two steps. First, we present a phonetic characterization of the dependent variable and its variants. Second, we…

In this research note I want to address some misunderstandings about the construct of redeployment and suggest that we need to fit these behavioural data from Yang, Chen and Xiao (YCX) into a broader context. I will suggest that these authors' work is not just about the failure of three models to predict equivalence classification. Equivalence…

An introductory phonetics course provides foundational content for future clinical practice and may serve as a student's first experience within the field of Communication Sciences and Disorders. The Students as Partners framework (Cook-Sather et al., 2014) offers a model for valuing student assets and experiences in co-creating learning materials…

Speakers vary in their pronunciations of the sounds in their native language. Listeners use lexical knowledge to adjust their phonetic categories to speakers' idiosyncratic pronunciations. Lexical information can, however, be inconclusive or become available too late to guide this phonetic retuning. Sentence context is known to affect lexical…