I met with a friend for a play date this morning who has a DD the same age as mine (18 months). Her DD was singing a couple of nursery rhymes over and over - not the words obviously, just the tune! - but it made me a bit worried that my daughter doesn’t do that at all. Is it normal to be singing songs by that age? My DD has about 30 words but I’ve never heard her sing a melody. Does anyone know?