Long before infants say their first words, they are acquiring communication skills that form the foundation of language. During their first months, infants demonstrate that they are social beings. They gaze into the eyes of their caregivers, and they are sensitive to the tones of the voices around them and to the facial expressions of those with whom they are interacting. They pay attention to the language spoken to them, and they take their turn in a conversation, even if it is just using vocalizations such as “cooing” sounds.

Infants are capable of producing intentional communication, and they are able to communicate specific desires and needs (Owens, 2005). In infancy, intentionality is signaled by the use of gestures, with or without vocalizations, coupled with eye contact and a persistent attempt to communicate a request. Infants cue their willingness to engage with their caregivers by providing nonverbal engagement cues (Bernstein & Levey, 2002). These include facial brightening, eye widening, smiling, head turning, and reaching for their caregiver. They also use disengagement cues that communicate the infant is “ready for a break” from an interaction. Disengagement cues include whimpering, frowning, and an increase in the rate of sucking (Brazelton, Koslowski, & Main, 1974).

Children’s early vocal development is usually described in terms of stages. These stages include the following (Bernthal & Bankson, 2004):

  1. Reflexive and cry vocalizations stage, which is observed during the first month of life.
  2. Cooing/gooing stage, in which basic syllable shapes of a consonant followed by a vowel (CV) are observed, and rounded back vowels (/o/, /u/) and back consonants (/k/, /g/) are produced, usually between 2 and 3 months of age. At this stage, children can distinguish between their mother’s voice and another voice and between utterances in a foreign language and those in their “mother” tongue.
  3. Expansion stage, which is characterized by vocal play or the exploration of the vocal mechanism, as infants produce squealing sounds and growling.
  4. Reduplicated or canonical babbling stage, in which the same consonant-vowel (CV) combinations are produced in repetitive strings, such as “nanana.” This pattern is observed at 6 months of age. Infants are able to follow their mother’s gaze and pointing, while showing a preference for exaggerated intonation patterns, slower productions, and a high pitch voice.
  5. Varied or non-reduplicated babbling stage, in which a variety of sounds and syllable strings that are not a reduplication of the same syllables increases. Infants at about 8 months of age begin to exhibit jargon, adultlike intonation patterns superimposed on rapidly produced multisyllabic strings of babble, which sounds like adult speech.
  6. Single words production stage, in which infants produce their first words at about 12 months of age.