The overly broad use of words, overgeneralizing their meaning typical of infants learning to talk.

-By 5 months of age, infants learn that their noncry vocalizations elicit reactions from social partners, and such responsiveness on the part of caregivers facilitates infants' development of phonology and speech and further promotes their social interactional abilities

-Reflexive (0-2 months). The first sounds infants produce are called reflexive sounds, which include sounds of discomfort and distress (crying, fussing) and vegetative sounds such as burping, coughing, and sneezing. Although infants have no control over the reflexive sounds they produce, adults often respond as if reflexes are true communication attempts. Parents ascribe communicative functions to even the earliest of infants' vocalizations. They ask infants questions such as "Why so much fussing?" to engage them in dialogue. Parents may even interpret infants' reflexive sounds out loud for them: "Oh, you're saying you want Mommy to hold you, aren't you?" Compared with nonparents, parents are usually more sensitive to infants' reflexive sounds and distress calls and report that they base their judgments about an infant's distress level on information they gain from the crying infant's face and voice.

-Control of phonation (1-4 months). In the control of phonation stage, infants begin to produce cooing and gooing sounds. Such sounds consist mainly of vowel-like sounds (sounds that approximate vowels but would not be transcribed as adult vowels). Infants in this stage might also combine vowel-like segments with a consonant-like segment (e.g., "aaam"). Other sounds in the control of phonation stage include isolated consonant sounds such as nasalized sounds (i.e., airflow is directed through the nose), as well as "raspberries," trills, and clicks. When infants produce consonant-like sounds, they typically do so far back in the oral cavity (e.g., "goooo"). These early consonant sounds are easier for infants to produce than are sounds that require more precise manipulation of the tongue, lips, or teeth (e.g., /t/ and /f/).

-Expansion (3-8 months). In the expansion stage, infants gain more control over the articulators and begin to produce isolated vowel sounds (those that would be transcribed as adult vowels), as well as vowel glides (e.g., "eeeey"). Infants also experiment with the loudness and pitch of their voices at this time, and they may squeal or produce a series of squeals. During this stage, infants may also use marginal babbling, an early type of babbling containing consonant-like and vowel-like sounds with prolonged transitions between the consonant and vowel sounds.

-Basic canonical syllables (5-10 months). In this stage, infants begin to produce single consonant-vowel (C-V) syllables (e.g., "ba," "goo"). Canonical babbling also emerges in this stage, and it differs from earlier vocalizations in that the infant produces more than two C-V syllables in sequence. Babbling may be reduplicated or nonreduplicated. Reduplicated babbling consists of repeating C-V pairs, as in "ma ma ma," whereas nonreduplicated babbling (or variegated babbling) consists of nonrepeating C-V combinations, such as "da ma goo ga." In many cultures, infants prefer nasal sounds (/m/, /n/, and the final sound in sing) and stop sounds (/p/, /b/, /t/, /d/) in their variegated babbling, combining such sounds variously with vowels to produce long vocalized sequences. Infants in this stage also produce whispered vocalizations, C-V combinations followed by an isolated consonant ("ba—g") and disyllables, which consist of two C-V syllables separated by an audible gap (ba—ba). Often, parents view their children as beginning to talk when the children begin to babble because such syllable combinations resemble adult speech.
Hearing infants are not the only babies to babble. Infants who are deaf, as well as infants who hear but have parents who are profoundly deaf, babble manually—using their hands. Just as the vocalizations of infants who hear speech mimic the specific rhythmic patterns that bind syllables, so do the hand movements of babies born to parents who are deaf. These infants' hand movements have a slower rhythm than that of ordinary gestures, and the infants produce these movements within a tightly restricted space in front of the body.

-Advanced forms (9-18 months). In the more advanced stage of early vocalizations, infants begin to produce diphthongs, which are combinations of two vowel sounds within the same syllable, as in the combination of sounds in boy and the combination of sounds in fine. Infants also begin to produce more complex syllable forms, including single-syllable types such as V-C ("am") and C-C-V ("stee"), complex disyllables such as V-C-V ("abu"), and multisyllabic strings with and without varied stress intonation patterns ("odago"). Probably the most noticeable achievement in the advanced forms stage is jargon. Jargon is a special type of babbling containing at least two syllables and at least two different consonants and vowels, as well as varied stress or intonation patterns. Because infants using jargon incorporate stress and intonation patterns, you may think you are hearing questions, exclamations, and commands, even in the absence of recognizable words.

What is it called when a child uses a word approximation for many different objects?

Which is an example of overextension?

Why do children overextend words?

What are the characteristics of infant directed speech?