The English language is not an easy language to master. Ask any ESL (English as a Second Language) student. With approximately 40 sounds (phonemes) for a 26 letter alphabet, it’s amazing how any child masters the language in their first few years of life. The development of speech sounds is predictable from child to child. Like any other developmental milestone there is a wide range of normal between children. Speech-Language Pathologists use developmental speech sound norms to determine if a child is making developmental or non-developmental sound errors.
In terms of speech sound development there are several different charts to follow. I find the following guidelines to be the easiest to understand.
For a more in-depth chart take a look at Eric Sander’s When are Speech Sounds Developed?, which is used by most pediatric Speech-Language Pathologists.
Speech is made up of two different levels: articulation and phonology. Articulation is the way sounds are produced when spoken. Phonology is the description of the system and patterns of phonemes that occur in language. A phonological process is a pattern that children use to simplify language. For an example, a child may mean to say “cat” but instead they say tat”. This process is called fronting, meaning a back sound (sound made with the back portion of the tongue) “k” is made in the front of the mouth instead producing “t”.
There are many types of phonological processes. As a child’s speech develops they gradually grow out of these phonological processes. The chart below lists each processes and when a child should no longer use them.
As phonological processes disappear and speech sounds are developed, a child becomes easier to understand. How well a child is understood is known as their speech intelligibility. Speech intelligibility is defined as how well other’s understand what is spoken. An easier way to think about your child’s speech development is to estimate his/her intelligibility. As a general guideline your child should be evaluated by a Speech-Language Pathologist if by …
Age 1 your child’s speech is NOT intelligible 25% of the time
Age 2 your child’s speech is NOT intelligible 50% of the time
Age 3 your child’s speech is NOT intelligible 75% of the time
Age 4 your child’s speech is NOT intelligible 100% of the time
Source: Caplan and Gleason, 1988
It’s important not to focus too much on “my child can’t make the “k” sound”, but rather to look at the whole picture. If you find your child is struggling to communicate with others seek out a Speech-Language evaluation. Why worry if you can seek out help and lead your child on the path of better speech?
Many children have isolated articulation or phonological delays, but others are impacted by delays in both speech and language. Next week I’ll be discussing language milestones, so be sure to check out that post.