Depends on the circumastances, when stressed/ excited / getting fed they make squeaking noises.
oinked like a pig
yes, Guinea pigs make low noises to tell that she/he feels sick
No it shouldn't, and that seems odd that it would do that.
Loud squeals and cries and even grunts.
Are you sure that the pig is getting upset? Maybe the little noises they make are affectionate noises. Guineas are very vocal and you can often assume they're grumpy when they are actually content.
They make the same noises that any other kind of pig makes :) They Grunt, Bark (not a dog bark) , a quiet hot panting- sounds like they are saying Hoff. but it is really weird like the air is going out of them, and a rough coughing noise. theres probably other noises but these are just the ones I could think of. You can do a google search of pig noises if you want.
A pig.
Oink or squeal.*snort snort* *oink oink*
Yes.
either its hungry or its just greeting you
Don't make loud noises? Or you could put him/her in the basement or somewhere quiet.