Speech Disorders

What is the difference between an Articulation Disorder and a Phonological Disorder?

An articulation disorder is a problem making sounds. Sounds can be substituted, left off, added or changed, and usually affects one or two sounds individually. For example, maybe a child substitutes and 'f' sound for a 's' sound (i.e. 'fwing' for 'swing') or an 'f' for a 'th' sound (i.e. 'fink' for 'think'). These substitutions do not affect an entire class of sounds; for instance, the substitution of f/s does not affect production of other similar sounds, such as 'z'.

A phonological disorder involves patterns of sound errors (phonological processes) that affect whole classes of sound and persist beyond what is considered developmentally appropriate. For example, substituting all sounds made in the back of the mouth like "k" and "g" for those in the front of the mouth like "t" and "d" (e.g., saying "tup" for "cup" or "das" for "gas"). All children demonstrate phonological processes when they are first beginning to speak, but when they continue to demonstrate these processes beyond what is considered typical, he or she may have a phonological disorder.

The diagram below is constructed from different sources and it should be treated with caution. Whilst it does provide insights into a plausible developmental sequence it should not be read as an invariant progression from one sound to another. Rather, it is a guide to a likely pattern of acquisition.

Vowels are generally considered to be acquired by the age of 3.

All children make predictable pronunciation errors when they are learning to talk like adults. These 'errors' are called phonological processes/phonological deviations. Listed below are the common phonological processes found in children's speech while they are learning the adult sound-system of English.

Bowen, C. (2011). Table 2: Phonological Processes. Retrieved from http://www.speech-language-therapy.com/ on 7/12/2021