Sighs. Many babies breathe irregularly during their first few months -- often even pausing, then sighing deeply before they resume. "The sigh is kind of the brain's way of taking control over the breathing again," says Kim Giuliano, M.D., a pediatrician at the Cleveland Clinic.
Grunts. For the first month, your newborn breathes only through her nose: If it gets stuffy, she may grunt or snort.
Gurgles. Your baby won't be able to voluntarily swallow extra saliva until she's close to a year old, so it either spills forward as drool or pools at the back of the throat. Result? Gurgling!
Coos. By experimenting with her tongue and voice, starting at around 2 months, she's warming up for her first word.
All of these sounds are perfectly normal, but keep your ears open for breathing that involves wheezing or whistling (a high-pitched shrill); that might signal a respiratory infection or other problems.