Link to this article: http://journals.cambridge.org/abstract_S0025100308003277How to cite this article: Julien Meyer (2008). Typology and acoustic strategies of whistled languages: Phonetic comparison and perceptual cues of whistled vowels.Whistled speech is a complementary natural style of speech to be found in more than thirty languages of the world. This phenomenon, also called 'whistled language', enables distant communication amid the background noise of rural environments. Whistling is used as a sound source instead of vocal fold vibration. The resulting acoustic signal is characterised by a narrow band of frequencies encoding the words. Such a strong reduction of the frequency spectrum of the voice explains why whistled speech is languagespecific, relying on selected salient key features of a given language. However, for a fluent whistler, a spoken sentence transposed into whistles remains highly intelligible in several languages, and whistled languages therefore represent a valuable source of information for phoneticians. This study is based on original data collected in seven different cultural communities or gathered during perceptual experiments which are described here. Whistling is first found to extend the strategy at play in shouted voice. Various whistled speech practices are then described using a new typology. A statistical analysis of whistled vowels in non-tonal languages is presented, as well as their categorisation by non-whistlers. The final discussion proposes that whistled vowels in non-tonal languages are a reflection of the perceptual integration of formant proximities in the spoken voice.

Many drum communication systems around the world transmit information by emulating tonal and rhythmic patterns of spoken languages in sequences of drumbeats. Their rhythmic characteristics, in particular, have not been systematically studied so far, although understanding them represents a rare occasion for providing an original insight into the basic units of speech rhythm as selected by natural speech practices directly based on beats. Here, we analyse a corpus of Bora drum communication from the northwest Amazon, which is nowadays endangered with extinction. We show that four rhythmic units are encoded in the length of pauses between beats. We argue that these units correspond to vowel-to-vowel intervals with different numbers of consonants and vowel lengths. By contrast, aligning beats with syllables, mora or only vowel length yields inconsistent results. Moreover, we also show that Bora drummed messages conventionally select rhythmically distinct markers to further distinguish words. The two phonological tones represented in drummed speech encode only few lexical contrasts. Rhythm thus appears to crucially contribute to the intelligibility of drummed Bora. Our study provides novel evidence for the role of rhythmic structures composed of vowel-to-vowel intervals in the complex puzzle concerning the redundancy and distinctiveness of acoustic features embedded in speech.