I'm worrying that DD might be harming DS's speech development.

[AmIWhatAndWhy]

DS is 3 and asd, DS is 2.

Echolalia is a big thing with Ds and he is all of a sudden talking like DD.
tbh I'm pleased he's talking at all but it is really silly things.

As an example, Dd says 'bye bye' when she doesn't want something. DS now says things like 'bye bye bedtime' when he means he doesn't want to go to bed. Previously he'd have said 'no bed'.

DD is two, sorry.

i wouldnt worry about it. my daughter was very echolalic age two now is fine. no speech/cognitive issues.

if he is using the phrases spontaneously in context then it is clever of him to pick up.

we all have "in family" phrases...

when he goes to nursery/school he will pick up other phrases.