This hypothesispredicts that within and across syllable patterns are based on rhythmicmandibular oscillations without independent tongue movements in infants fromthe onset of babbling (e.g. /bÉ™/, /di/, /gu/ ). The term ‘frame’ concerns how regular the oscillation of the mandibular is that results in rhythmical syllable-like structure whereas ‘contents’ applies to the period in development when children acquire the ability to to move the articulators independently when emitting a series of syllables. The hypothesis, originally put forward in 1990, has been subject to criticisms as well as a robust defence.
See Articulation, Babbling, Speech development, Syllabic structure