Air forced down them produced different vowel sounds, and half of the models had an extra chamber to mimic an air sac. (newscientist.com)
It may be that elephants can subtly alter a call, simply by changing the position of their lips and tongues, just as humans do to produce different vowels, King says. (sciencemag.org)
• Encourage your twins to use different vowels and speech sounds. (multiplesandmore.com)