Having spent his childhood in the Middle East, Parviz did not begin speaking English until he was a teenager. When he pronounces words such as "mother," native English speakers hear a word that sounds more like "mudder." Which of the following is the best explanation for this phenomenon?

He lost the ability to produce sounds he didn't hear in his native language.

Explanation:

Language development takes places since birth and it goes through a series of different stages, even when we cannot still produce words, we are already developing language by listening to other people's language, babbling and imitating sounds when we are babies.

However, there are also some skills that little babies have and that they lose as they grow older. One of these skills is the ability to differentiate sounds that don't belong in their language. Babies and kids can differentiate these sounds but as they grow older they begin to only recognize sounds that belong to their native language.

In this case, Parviz did not begin speaking english until he was a teenager, therefore, he cannot pronounce the phoneme used in the word "mother", since it doesn't exist in his native language and it comes out as "mudder". This happened because he lost the ability to produce and differentiate sounds he didn't hear in his native language.