Mr W( 3Y4M) is not on the spectrum at all - had PP from a very early age. When he was 4 months he would watch people play piano for hours. At one year he would play notes on his kiddie piano to match the music he heard. He can sing just about any song he hears a cappella almost perfectly and knows about a hundred songs. He has his own jazzy versions of a lot of songs. He also makes up his own verses. He now corrects DW and me when we do not sing a song perfectly.