In my previous post, I discussed the pronunciation of tomato with an American accent by my grandson Oliver, which seems to be influenced by TV. However, most of his pronunciation seems to be influenced by the people around him, though it can deviate from the way his parents speak.
For example, he has [f] at the start of three, while both his parents have [θ]. And his favourite word why has a vowel that sounds like [ɔɪ] rather than the [aɪ] that his parents have. Both these features of pronunciation may be attributed to the influence of London accent.
This illustrates that we tend to learn our pronunciation from our friends and the people around us but often do not sound like our parents.