Yet we can listen to what a 17 month old child says and hear patterns common to child speech/language development. This blog entry is a brief review of speech development from birth – age 5. The information is adapted from a book by Ken M. Bleile. (1) The American Speech Language Hearing Association also provides information about speech/language development at http://www.asha.org/.
From birth to about 12 months of age, children begin to perceive the specific speech sounds of the language(s) they hear around them. When we talk, we create an acoustic signal, a sound wave full of information. The young child must decipher this signal. She has to find the individual ‘segments’ that are letter sounds and words. Imagine yourself listening to a language you don’t know; it sounds like a jumble of sounds, not an understandable sequence of words. “The acoustic signal of speech shows no distinctive boundaries that might mark where one segment ends and another begins, and the acoustic properties that can be associated with any particular segment are spread over fairly broad temporal regions.” (2) The young child listens to intonation patters, facial expressions, and watches his environment closely to discover the speech and language code hidden in the acoustic signal.
At the same time, brain and physical development are giving the child greater control over his body, including his jaw, tongue, lips, chest and lots of other muscles needed for saying sounds of his own. His babbling is his way of practicing these sounds. He tries out new sounds, combines them in different ways, hears his own voice and sees what affect it has on others. Gradually, he controls this babbling by starting and stopping it precisely enough that the people around him hear “words.” These beginning words don’t sound exactly like adult words. But they are close enough to give him a new kind of power. He can get what he needs with speech.
Once the child has figured out 1.) the acoustic signal actually made up of sound segments and 2.) she has greater control over saying sounds, she must learn the language rules of her community. A speaker of French must learn the rules of the French language. These rules are different than the rules of Spanish, or English, or any other language. And so the child must match her new physical ability to make sounds with a gradual understanding of how these sounds are combined in her native language. These two forces - the mechanics of speech and the rules of language – create some common “Error Patterns.” It is expected that children from the age of 2 years to 5 years will not speak like little adults! They will have natural, normal “error patterns” in their speech. A speech language pathologist listens carefully to a child and looks for these error patterns. It helps her decide if a child needs extra help learning to talk.
Note: “Regressions, small and large, occur commonly in speech development, especially during Stage 2, and may last from days to months. Parents sometimes notice larger, longer-lasting regressions, commenting that a child “used to say it correctly, but now doesn't” …Rather than proceeding in a straight line, speech development zigzags and sometimes even regresses… (3) While it may be normal to see regressions, we do want to take care that a child's regression is not due to hearing loss, environmental deprivation, or developmental delays. Consultation with the child's pediatrician, school district, or private clinician may be helpful.
(1) Manual of Articulation and Phonological Disorders: Infancy through Adulthood, 2nd Edition (© 2004, Clifton Park, NY: Thomson Delmar Learning, Inc.).
(2) Nittrouer, Susan (2002) From Ear to Cortex: A Perspective on What Clinicians Need to Understand About Speech Perception and Language Processing, Language Speech and Hearing Services in Schools,33, p. 238.
(3) Bleile p. 120