Developing a corpus of spoken language variability

We are developing a novel, searchable corpus as a research tool for investigating phonetic and phonological phenomena across various speech styles. Five speech styles have been well studied independently in previous work: reduced (casual), careful (hyperarticulated), citation (reading), Lombard effect (speech in noise), and ‘‘motherese’’ (child‐directed speech). Few studies to date have collected a wide range of styles from a single set of speakers, and fewer yet have provided publicly available corpora. The pilot corpus includes recordings of (1) a set of speakers participating in a variety of tasks designed to elicit the five speech styles, and (2) casual peer conversations and wordlists to illustrate regional vowels. The data include high‐quality recordings and time‐aligned transcriptions linked to text files that can be queried. Initial measures drawn from the database provide comparison across speech styles along the following acoustic dimensions: MLU (changes in unit duration); relative intra‐speaker intensity changes (mean and dynamic range); and intra‐speaker pitch values (minimum, maximum, mean, range). The corpus design will allow for a variety of analyses requiring control of demographic and style factors, including hyperarticulation variety, disfluencies, intonation, discourse analysis, and detailed spectral measures.