Noisy tort

[Glosseryck]

So I have a greek tort, and he's great! But he does make some sounds every now and again. He's completely quiet when breathing, but sometimes he can do a little sigh if he bumps into things or if he thinks I haven't given him nice food. He loves to sit in my lap and when he does he makes a creeking noise similar to a frog. Is this normal? I asked on another site and they said he could have breathing problems and that it's not normal, but since he never makes sounds when breathing I don't think that's the case. Is he just a vocal tort? Could it be a sign of old age? I unfortunately don't know his age since he's a rescue. His last home had him for seven years but they adopted him from a rescue that found him walking around in a city. In those seven years he hasn't grown.

I am a new tort owner but I've done my research and haven't found any information that I think quite suits this case.