Handbook of Language and Literacy Development - a Roadmap from 0 to 60 Months

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Introduction to Vocalizing 7 - 9 Months - More Sounds, More Intentionallyclick to print Print
Research Review / Parent

Written by: Carrie Gotzke and Heather Sample Gosse, University of Alberta

While the four- to six-month period was a time of vocal play, seven- to nine-month-old infants communicate more intentionally. Vocalizations have a more consistent meaning and infants learn that their signals have specific effects on their caregivers. Continued successful communication development depends both on the ability of the infants to signal messages clearly and the ability of their caregivers to interpret those signals. Vocal skills continue to develop in the context of interaction with others. For information on this critical context, please refer to Interacting 7 – 9 Months.

Oral Control - The Foundation for Expanding Vocal Skills

By eight months, increasing control over the lips allows infants to keep their lips sealed while chewing and swallowing semi-liquids, like applesauce (Owens, 2001). Infant chewing becomes more advanced, changing from a vertical to a more rotary pattern. Increased control of the tongue is also exhibited as infants become able to move food from side-to-side using more lateral tongue movement. Increasing control over the lips, jaw and tongue is essential to the development of more complex and variable vocalizations during this time.

Vocalizations – New Sound Patterns

Seven- to nine-month-old infants produce a greater variety of vocalizations than they did in the previous six months. Vocalizations now contain more syllables and different consonants and vowels.

Reduplicated Babbling

In the three- to six-month period, babbling consisted primarily of single syllable sounds. With further development of the respiratory system, infants become able to produce multiple sounds with a single breath. Typically around seven months, infants begin repeating a single syllable to produce consonant-vowel syllable strings, such as “ma-ma-ma-ma-ma-ma.” This type of vocalization is called reduplicated babbling (Owens, 2001; Sachs, 2005). Initially, the purpose of reduplicated babbling is self-stimulation, not communication. Gradually, this type of babbling will be heard in a variety of contexts but most often when infants are exploring the environment or holding an object. By eight months, reduplicated babbling may also be used in imitation games with caregivers. The sounds produced during this stage resemble adult speech in terms of their resonance and timing. Early speech sounds are limited to bilabial and alveolar stops (e.g., /p, b, t, d/), nasals (e.g., /m, n/ and “ng” as in “sing”) and the glide /j/, as in “yell” (Owens, 2001). The bilabial and alveolar stops are produced most frequently during this time (Menn & Stoel-Gammon, 2005).


Echolalia is defined as “speech that is an immediate imitation of some other speaker” (Owens, 2001, p.87). Imitation by infants was first noted in the three- to six-month period when infants imitated the tone and vowel sounds of their caregivers’ speech. By eight months of age, infants will imitate the pitch and contour patterns of their environmental language. Infants also begin to imitate individual sounds, but only those sounds they are able to produce spontaneously.

Variegated Babbling

Around eight months of age, variegated babbling, in which different syllables are repeated (e.g., “bagidabu”) appears (Owens, 2001; Sachs, 2005). Other sound sequences such as vowel-consonant-vowel and consonant-vowel-consonant, where the vowel and consonant are maintained (e.g., “apa” and “pap”) may also be heard. There is disagreement among researchers with respect to whether reduplicated babbling is followed by variegated babbling or if these types of babbling overlap.


Jargon, which is described as long strings of unintelligible sounds with adultlike prosodic and intonational patterns, also begins to heard around eight months of age (Owens, 2001). an infant’s jargon will resemble the prosodic patterns of the language of his or her environment. An example of jargon may be the syllable string “ah babi babu” produced with a rising intonation. It is important to note that jargon does not contain true words. Infants vary in the amount of time spent producing jargon and the amount of jargon produced.

Vocalizations – Expressing Intentions

While seven- to nine-month-old infants produce a greater variety of vocalizations, they are also communicating a greater variety of messages while vocalizing. The development of intentional communication is a key to their new skills.


Beginning at about nine months, infants produce consistent vocal patterns that function as words for the infant (Owens, 2001). These vocalizations are called protowords or phonetically consistent forms (PCFs) and are often accompanied by gestures. For more information on gestures, see Interacting 7 – 9 Months.

Protowords function as words for the infant but are often imitations of environmental sounds and are not based on adult words (Owens, 2001). Four patterns of protowords have been identified: 1) single or repeated vowels, 2) syllabic nasals, 3) syllabic fricatives, and 4) single or repeated consonant-vowel syllables. An example of a protoword may be “ooo ooo” for juice. It is important to note that protowords have stable sounds, syllable shape, and prosody and are used for specific functions, such as requesting or to gain their caregiver’s attention. Protowords are considered to be evidence that infants are realizing that there is a connection between sound and meaning and are thus considered to be an important transitional step in the development of words.


As infants play with their developing vocal mechanism, they learn to express messages using different intonation patterns (Owens, 2001). Using these intonation cues, caregivers may be able to recognize when their infant is frustrated or pleasantly surprised and when their infants are conveying greetings or requests.

Intentional Communication

Intentional communication occurs when infants purposefully act or vocalize in order to acquire their caregiver’s attention or help (Sachs, 2001). Although caregivers often attribute intentionality to their infants in the first six months, true intentional communication begins to emerge around eight months. Four criteria have been developed for identifying intentionality. The following criteria are from Sachs, 2005:

  1. “The child makes eye contact with the partner while gesturing or vocalizing, often alternating his or her gaze between an object and the partner.
  2. The child’s gestures and vocalizations have become consistent and ritualized. For example, a child used a gesture of opening and closing her hand when she wanted something, rather than attempting to reach the object herself. The vocalization she used, ‘eh, eh’ was one that she consistently used in situations in which she wanted something. Another child would probably use a different sound in the same situation, because this sound was not copied from adult speech but rather was a communicative signal invented by this child.
  3. After a gesture or vocalization, the child pauses to wait for a response from the partner.
  4. The child persists in attempting to communicate if he or she is not understood and sometimes even modifies behavior to communicate more clearly” (p. 43).

Before infants become intentional communicators, they must first learn that there are causes for events (Sachs, 2005). Since birth, caregivers have been helping their infants learn this relationship by responding with food or comfort when their infants cried. Secondly, infants must also have learned that they can manipulate the people in their environment in order to carry out their goals. It is likely that intentional communication emerges as the result of the interaction of many factors including biological changes in the nervous system, nonlinguistic cognitive development, social cognitive development, and experience.

Gotzke, C. & Sample Gosse, H. (2007). Research Review: Vocalizing 7 - 9 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 8. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development