Dd is three, when she's happy and running around she makes this noise.. it's hard to explain but it's like a constant grunt/groan/hum. Ugghm ugghm ugghm x100 is the best way to describe it 😂
It's mixed in with squeals and laughter, it's definitely not a physical problem like a breathing issue. Just a happy sound? We've been getting a few funny looks from the neighbours when she plays outside which has prompted me to ask, is this something all toddlers do?