Check out this video highlighting child language acquisition research conducted by Toby Mintz, Associate Professor of Psychology and Linguistics at the USC College of Letters, Arts & Sciences, and USC College undergraduate Ashlee Welday.

Their study investigates how infants are able to identify individual words in their language, as opposed to hearing speech as a continuous string of sound with no internal word boundaries.  The researchers use an artificial language with vowel harmony to discover if infants, even those exposed to a language devoid of vowel harmony as is the case with English, are innately equipped to pick up on vowel harmony as a cue for word boundaries.

They find that infants do use vowel harmony as a cue to help decipher word boundaries, in the way we would predict if babies were innately equipped to perceive vowel harmony.