AI Reveals Human-Like Vowels in Sperm Whale Calls

Sperm whales maintain matrilineal families and cultural groups using short click sequences known as codas. In 2024, researchers at Project CETI and the Massachusetts Institute of Technology identified a “phonetic alphabet” built from rhythm, tempo, rubato and ornamentation across roughly 9,000 codas. Establishing how those elements combine matters because it tests whether highly structured communication is uniquely human and could support whale conservation and eventual interspecies communication.

A Project CETI and University of California, Berkeley team published its latest findings in Proceedings of the Royal Society B on April 16. Machine-learning analysis covered more than 1,100 codas recorded near Dominica from 2014 to 2018, involving 15 female sperm whales and calves. Researchers identified two vowel-like categories resembling “a” and “i,” differences in vowel duration and evidence of coarticulation between adjacent sounds. The group aims by 2031 to understand about 20 expressions, including signals linked to diving and sleeping.