When Ds (13 months) is sleeping he takes sharp quick intakes of breath (almost like a newborn with wind) it seems to be while he's dreaming as sometimes he will babble a little or let out a little cry.
His breathing doesn't seem obstructed at all and no snoring. It will be normal and then he will take a few very short sharp breaths in, it never usually lasts ling and once he's settled his breathing if very calm and normal.
The only way I can explain it is, if you have ever had a toddler fall asleep after a really good cry and they kind of hiccup air in for a while until the calm into their sleep. Sorry I'm not very good at describing it!