Phonological development refers to the gradual acquisition of an adultlike system of speech sounds that are used to convey meaning in a language. Phonological development can be considered in terms of both perception and production of speech sounds.
Historically, the development of speech sounds has been characterized in terms of the development of articulation abilities, with recent attention being paid to the notion that a larger set of rules and linguistic representations may also govern how individuals acquire speech sounds.
Research has demonstrated that infants are aware of speech sounds long before they are able to produce them. For example, infants at 1 month of age are able to discriminate speech sound categories such as the difference between phonemes /p/ and /b/ (i.e., categorical perception; Eimas et al. 1971). Over time, infants also develop the ability to track features of speech such as prosody (i.e., changes in pitch and loudness or the “melody” of speech) and stress patterns, as well as realize which distinctions between sounds are not meaningful in their native language (e.g., variability between speakers producing the same sound as in the case of a male versus female speaker, versus the meaningful difference between two distinct speech sounds). In addition, infants as young as 6 months of age have been shown to track the frequency with which speech sounds occur within a speech stream (i.e., phonotactic characteristics) (Saffran et al. 1996), a skill that has been linked to later vocabulary learning. In addition, by 10–12 months, infants demonstrate a reduced ability to recognize nonnative speech sound contrasts as the infant appears to have honed in on the sounds that occur within the language(s) to which he or she has regularly been exposed. It is in this early period that infants typically begin to demonstrate recognition of single words. During the second year of life, infants refine their vocabulary comprehension abilities to be able to discriminate between words that sound very similar (e.g., “bih” and “dih”) and associate those words to new objects that are encountered in the environment, recognize words when provided with only a portion of the relevant phonetic information, and are able to comprehend words even if they are mispronounced. Perceptual abilities continue to progress as the child begins to associate phonological features with aspects of spoken language (see chapter “Phonological Awareness”).
Infants begin to explore and experiment with their vocal tracts from birth. The earliest sounds that are produced are reflexive vocalizations, such as sneezing and breathing. As the infant matures, sounds include cooing and laughter, with increased variety of consonant and vowellike sounds. Vowel sounds are typically produced the earliest, followed by consonant-like approximations that are produced in the back of the throat (e.g., /g/ and/k/) which are then followed by sounds that are produced in the front of the mouth (e.g., /m/, /n/, /b/, /p/). In addition to adding new sounds to the repertoire, the speech sounds are combined in sequences of increased length and complexity as the infant engages in vocal play. From 6 to 10 months, infants typically produce “reduplicated” syllables (i.e., repeated syllables containing the same consonant and vowel, e.g., “babababa”). From 10 to 14 months, babbling incorporates more variety in terms of sounds/syllables and pitch contours and is referred to as “nonreduplicated.” In addition, at approximately 1 year of age, infants use speech sounds to produce their first spoken words. In typical development, spoken vocabulary continues to grow well into school age and beyond.
Weak syllable deletion: omission of an unstressed syllable in the target word, e.g., “nana” for “banana.”
Final consonant deletion: omission of the final consonant in the target word, e.g., “ca” for “cat.”
Reduplication: production of two identical syllables based on one of the target word syllables, e.g., “baba” for “bottle.”
Consonant harmony: target word consonant takes on features of another target word consonant, e.g., “guck” for “duck.”
Consonant cluster reduction: omission of a consonant in a target word cluster, e.g., “top” for “stop.”
Velar fronting: a sound that is typically produced at the back of the mouth (e.g., /k/ or /g/) is replaced by a sound that is produced further forward, e.g., “ti” for “key.”
Stopping: a fricative (i.e., a consonant that is produced with friction such as /s/, “sh,” /f/, or /v/) is replaced by a stop consonant in which airflow is completely obstructed (e.g., “ti” for “sea”).
By early school age, most phonological processes have resolved in typical development, as the child’s productions more closely match the adult form. However, some children demonstrate lingering phonological processes that impact intelligibility (see chapter “Phonological Disorders”).
Current research in phonological development is exploring the existence of what would be considered linguistic universals that govern all languages versus the acquisition of language-specific phonological rules.
In addition, a body of research exists that explores phonological development and its impact on the acquisition of reading and writing skills, in hopes of developing targeted instructional techniques for academic success.
References and Reading
- American Speech-Language-Hearing Association (ASHA). (1993). Definitions of communication disorders and variations. American Speech-Language-Hearing Association, 35(Suppl. 10), 40–41.Google Scholar
- Chomsky, N., & Halle, M. (1968). The sound pattern of English. New York: Harper & Row.Google Scholar
- Gierut, J. (2008). Treatment efficacy summary: Phonological disorders in children. Retrieved 1 May 2011, from http://www.asha.org/public/EfficacySummaries.htm
- Hoff, E. (2005). Language development. Belmont: Thomson Wadsworth.Google Scholar
- Ladefoged, P. (1982). A course in phonetics (2nd ed.). London: Harcourt Brace Jovanovich.Google Scholar
- Vihman, M. (1996). Phonological development. The origins of language in the child. Oxford: Blackwell.Google Scholar