I've been worrying about a sound/behaviour my DD (7 months) makes for a while now (since 3-4 months at least) and whether it's some early indication of being neurodivergent, however as a FTM with very little exposure to babies prior to having my own, I realised I don't actually know what's normal and what's not.
The sound I've been worrying about is like a humming sound, but in a strained/tensing sort of way rather than the gentle humming with a song. She does it at least 50% of her awake time. She has always had horrendous reflux and I thought it was a sign of discomfort as she used to do it (still for extended periods of time) before being sick or doing a large beltch. But she also does it when I'm not convinced it's because she's in discomfort, like when she's playing or weaning. She also whimpers a lot, both noises increasing the more tired she becomes.
Is this normal? My concern is that it's a vocal stim.