title: A multimodal spectral approach to characterize rhythm in natural speech.
abstract: Human utterances demonstrate temporal patterning, also referred to as rhythm. While simple oromotor behaviors (e.g., chewing) feature a salient periodical structure, conversational speech displays a time-varying quasi-rhythmic pattern. Quantification of periodicity in speech is challenging. Unimodal spectral approaches have highlighted rhythmic aspects of speech. However, speech is a complex multimodal phenomenon that arises from the interplay of articulatory, respiratory, and vocal systems. The present study addressed the question of whether a multimodal spectral approach, in the form of coherence analysis between electromyographic (EMG) and acoustic signals, would allow one to characterize rhythm in natural speech more efficiently than a unimodal analysis. The main experimental task consisted of speech production at three speaking rates; a simple oromotor task served as control. The EMG-acoustic coherence emerged as a sensitive means of tracking speech rhythm, whereas spectral analysis of either EMG or acoustic amplitude envelope alone was less informative. Coherence metrics seem to distinguish and highlight rhythmic structure in natural speech.
authors.affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Alexandrou
authors.affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Saarinen
authors.affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland.
authors.forename: Jan
authors.initials: J
authors.lastname: Kujala
authors.affiliation: Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Salmelin
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D010507:Periodicity; D013018:Sound Spectrography; D013060:Speech / Q000502:physiology*; D013061:Speech Acoustics; D013068:Speech Production Measurement; D055815:Young Adult