Imo seems like the bare minimal to be considered life is they replicate on their own and continue on to survive. I don't see us too far off from making machines capable of doing that. I suppose like all animals on earth, we have to follow some basic rules / laws of interaction to all live. So our behavior, even with if they were machines, has to be somewhat similar. I don't see any reason they have to look or sound the same though. I mean sound itself is a frequency range, they can operate in one we don't hear.