The subject of this study is to identify unknown speakers particularly from their speaking tempo represented in Speech
Rate SR and Articulation Rate AR as temporal parameters. The fundamental goal of this study, on the acoustical level, is to prove acoustically that every speaker has a significant speech rate SR and articulation rate AR through which the unknown speaker can be discriminated and to investigate which of them (SR or AR) could be of more benefit for identifying unknown speakers and to what extent. Also, the present study is essentially concerned, on the perceptual level, with listeners' perceptual abilities in perceiving and differentiating different speaking tempo for identifying unknown speakers in order to utilize this exceptional ability in forensic speaker identification FSI; aiming to provide some useful acoustical and perceptual data to be used in forensic phonetic filed. The most important characteristic of the temporal aspects of speech, that they are not easily disguised or imitated by accent or fundamental frequency leveling; so they could be useful for identifying unknown speakers particularly in forensic phonetic field.
The speech rate SR and articulation rate AR of ten unknown speakers / informants of colloquial Arabic are calculated. The
speakers were recorded while talking spontaneously for a radio program. Only 30 seconds of speech are cut for each speaker from the entire episode. After that 60 naïve listeners are asked to listen carefully to the 10 unknown informants in order to mark the fastest speaker and the slowest speaker depending only on their ears.