Baby making unusual noises

My 5-month-old has been discovering his voice which has been fun for the most part. However, my wife and I have noticed a weird noise that he makes lately. It's hard to describe, but it sounds like when he takes in a breath, he lets out a series of little gasps or spurts that sound like a whooping noise. He doesn't appear to be in distress of any kind (teething aside), no fever, cold, cough, or any of that. Is the little one playing with sounds or has anybody had their little one go through something like this?