Patterns of voice disguise in forensic cases involving speaker identification or speaker profiling may contain clues to features of the undisguised voice of a speaker. In a longitudinal and synchronous study, 100 subjects were asked to read a text on five occasions during a period of six months, first using their normal voices, and subsequently with two out of three modes of voice disguise, (1) raising fundamental frequency, (2) lowering fundamental frequency, (3) denasalization by firmly pinching theirnose. The focus of this investigation is on fundamental frequency (F0). Results show that most subjects were in fact able consistently to change their F0 according to the mode of disguise they had selected. However, there were differences between both sexes with regard to their preference of disguise modes as well as to the individual articulatory ‘strategies’ which they employed to implement them. Results corroborate experience with forensic casework, that is, they show that there is a constant relation between the F0 of a speaker’s natural speech behaviour and the kind of disguise he willuse in an incriminating phone call. Speakers with higher-than-average F0 tend to increase their F0 levels. This process may or may not involve register changes from modal voice to falsetto. Speakers with lower-than-average F0 prefer to disguise their voices by lowering F0 even more and often end up with permanently creaky voice. Thelatter trend can be observed much more clearly in males. Females are generally more reluctant to make drastic changes to their fundamental frequency patterns.

Effects of voice disguise on speaking fundamental frequency

Speaker-individuality in suprasegmental temporal features: Implications for forensic voice comparison.

Forensic reference data on articulation rate in German.

Arabic audio clips: Identification and discrimination of authentic Cantillations from imitations

1 MATURING TEMPORAL BONES AS NON-NEURAL SITES FOR TRANSFORMING THE SPEECH SIGNAL DURING LANGUAGE DEVELOPMENT Developmental events in the temporal bones shift the pattern of a given speech sound’s acoustic profile through the time children are mapping linguistic sound systems. Before age 5 years, frequency information in vowels is differentially accessible through the years children are acquiring the sound systems of their native language(s). To model the acoustic effects caused by developing temporal bones, data collected to elicit steady-state vowels from adult native speakers of English and Diné were modified to reflect the form of children’s hearing sensitivities at different ages based on patterns established in the psychoacoustic literature. It was assumed, based on the work of psychacousticians (e.g., Werner, Fay & Popper 2012; and Werner & Marean 1996), that the effects caused by immature temporal bones were conductive immaturities, and the age-sensitive filters were constructed based on psychoacoustic research into the hearing of infants and children. Data were partitioned by language, sex, and individual vowels and compared for points of similarity and difference in the way information in vowels is filtered because of the constraints imposed by the immaturity of the temporal bones.

H.R. Masthoff

Papers

The relation between speech tempo, loudness, and fundamental frequency: an important issue in forensic speaker recognition