A new study finds that chatty monkeys in Ethiopia may offer clues into how the power of speech evolved in humans. NPR's Gregory Warner reports the reason has to do with something all of us do every day without noticing.

GREGORY WARNER, BYLINE: That something was first noticed in 1899 by a French laryngologist, which my French-speaking colleague, Ofeibea Quist-Arcton, will now demonstrate.

Read the full transcript and listen to the interview "Ethiopian Monkey Study Offers Clues Into How Human Speech Evolved" at NPR.