Remember when your child was a toddler and he would say “tat” for “cat” but ‎was able to say “banana” or “umbrella clearly”? And then there came a time when perhaps “banana” was contracted to ‎‎“nana” and cause for some concern ! Or perhaps you now have a kindergartener or a child in Year 1 who states ‎that “a banana is lellow” and that he “yikes a chocolate milkshake”. Or another who would like a “poon” for her ice-‎cream please.‎
Quite simply the above examples are speech sound disorders in progress. As children develop and mature, their neurological system (brain) becomes hard-wired to work more efficiently; ‎instead of learning things in discreet units which can be uneconomical, the brain starts establishing rules by which ‎speech sounds in the language the child is exposed to are ordered. ‎This naturally provides an efficient base upon which later speech sounds and rules are built upon.
An example of a speech sound rule in the English language would be; if there are 2 consonants together in a word ‎the voicing component will be the same. i.e: / laps/; has 2 consonants together at the end of the word. /p/ and /s/ are ‎both similar sounds in that they are not voiced.‎
‎ /labs/ has also similar sounds in word final position. However, /b/ and /z/ (although spelt “s” it is pronounced as a “z”) are ‎voiced correlates of “ps”. And no, obviously the child is not aware of these rules and neither are most natural ‎speakers of a language. The magnificent, marvellous brain does that for us; and speechies like me, are trained to figure what rules the brain ‎has learnt in error that underlie the speech sound disorder that a child displays. We then devise an intervention ‎program to undo rules that have been established in error or to establish the learning of new rules. In a nutshell, that ‎is what speech sound therapy is all about.‎
If a child is exposed to more than one language, the brain does go about working on the rules for each language
simultaneously. ‎There is a slight delay in the acquisition of language for children who are exposed to more than one language consistently. The brain ‎does get the job done albeit a little slowly depending on the number of languages it may have to process. All said and done though, ‎this happens while the child is busy and immersed in their language rich environment.