My youngest DD is very loud - and was from birth - we were still in the operating theatre and one of the nurses said, "She's got a good set of lungs on her!" ROFL. So when she's loud, she's very loud! LOL

However we also had her in at the doctor last year for glue ear. So I would say to get those little ears checked out. For some kids it's behavioural (which is why 5 point scales & the words "inside voices" were invented) but your DD is very little so I don't think you can just excuse it without getting it checked out.