Developmental stages of pre-speech vocalizations (e.g., as described by Carol Stoel-Gammon in 1998) are not discrete, and vocalizations from previous stages continue to be uttered subsequently. Novel emergent behaviors define the beginning of a new stage. Ages are assigned to each stage as estimates only, because children differ greatly regarding the timing for recording milestones of early language development.
The first stage (from zero to two months), phonation, is characterized mainly by fussing, crying, sneezing, and burping, which bear little resemblance to adult speech. The second stage (at two to three months), cooing, begins when back vowels and nasals appear together with velar consonants (e.g., \gu\, \ku\). Cooing differs in its acoustic characteristics from adult vocalizations and is recorded mainly during interactions with caregivers. In the third stage (at four to six months), vocal play or expansion, syllable-like productions with long vowels appear. Squeals, growls, yells, bilabial or labiodental trills, and friction noises demonstrate infants’ playful exploration of their vocal tract capabilities during this stage.
In the extremely important canonical babbling stage (at seven to ten months), two types of productions emerge: reduplicated babbling—identical, repetitive sequences of CV syllables (e.g., \ma\ma\, \da\da\); and variegated babbling—sequences of different consonants and vowels (e.g., CV, V, VC, VCV = \ga\e\im\ada\). Such productions are not true words, as they lack meaning. Canonical babbling is syllabic, containing mainly frontal stops, nasals, and glides coupled with lax vowels (e.g., \a\, \e\, \o\). The emergence of canonical babbling is highly important, holding predictive value for future linguistic developments. Oller and her colleagues in 1999 argued that babies who do not produce canonical babbling on time are at high risk for future speech and language pathology, and should be carefully evaluated by a language clinician.
In the fifth stage (at twelve to thirteen months), jargon or intonated babble, infants produce long strings of syllables having varied stress and intonation patterns. Jargon sounds like whole sentences conveying the contents of statements or questions, and often co-occurs with real words. Yet, it lacks linguistic content or grammatical structure.
Read more: Babbling and Early Words – Stages In The Development Of Pre-speech Vocalizations – Months, Canonical, Vowels, and Productions – JRank Articles http://social.jrank.org/pages/68/Babbling-Early-Words-Stages-in-Development-Pre-Speech-Vocalizations.html#ixzz3m1SGGywThttp://social.jrank.org/pages/68/Babbling-Early-Words-Stages-in-Development-Pre-Speech-Vocalizations.html