Yes, over here!
DS started talking around his 2nd birthday and became a real little chatterbox, and was quite an "out loud thinker".
However, he's always been shy and very wary of new people.
He started nursery at 2y10m and was very reluctant. Lots of tears, it was quite tough.
About 2 weeks in his keyworker asked us if he spoke at home ?! I was honestly flabbergasted and was like Yes, all the time. She said he hadn't uttered a word.
There was talk of SEN and special meetings and I was getting quite worried, but was always reassured that he was actually a perfectly "normal" and chatty boy at home and with family.
Over time, with a very low pressure/ hands off approach at nursery, he started chatting to 1 or 2 teachers (the quieter, friendlier females) and a few close friends.
By the time he was 4 he'd talk to nearly anyone but was always quiet.
Now at school, he's a total character and there's no evidence of thr selective mutism.