Dec. 26, 2019, 7:19 a.m.

By The Age Of 6-7, Most Children Make Their Speech Sound Like The Adults Around Them

Interesting fact: Babies are better at hearing different sounds (with different accents) around them as compared to adults! 
But this usually happens during the ages of 6-12 months. They can actually “hear” the differences between different languages and their accents. Gradually, by the age of 12 months they start losing this ability. But as they lose this ability to hear these differences, they develop the ability to distinguish between sounds of the same language, simultaneously. One could call this a “sound map”. This map is usually an accurate representation/example of each and every sound they hear (that acts a base) along with an area or bubble around that sound which can accommodate similar sounds. 
(Sound + Similar sounds) * ∞ = Sound Map
The sounds that act as base are called prototypes. These prototypes largely affect how children hear speech and in relation to that, end up babbling and then gradually talking. Even when adults don’t speak clearly, these prototypes help them understand clearly.
By the time they’re around 6-7 years of age, they start pronouncing words like the adults around them or at least attempt to sound like them. This is because these are the sounds they’ve heard that made the “prototypes” in their brains.