There is a perennial question: What do animals understand? In a new paper Cat Hobaiter and her colleagues ask: Are ape gestures like words? They report that chimpanzees use what may be understood as individual identifiers (like some cetaceans). As Hobaiter notes in a BBC interview, the distance between human and non-human communication is shrinking all the time. But in this connection it seems to me important to consider the internal structure of both words and speech sounds.The internal structure of speech sounds was first identified In 1669, analysed much more deeply by Chomsky and Halle in 1968, and now accepted by the overwhelming majority of linguists. In the M sounds in Mummy and the D sounds in Daddy there are at least four critical ‘distinctive features’. Such features characterise all human languages, spoken and signed. But it hasn’t been shown that there is any equivalent of this in gestures by apes, So in answer to Hobaiter’s question: Do chimpanzees use words? there is seemingly no evidence yet that they do.