Our seven year old male overweight neutered cat Inky has always been very vocal, he will carry on a conversation with you if you like. We've had him since a kitten, and he's always been that way. Over the past few days I've noticed him starting to lose his voice, and now it's almost completely gone. Today I also noticed him gulping a lot. What is causing this? I am worried it might be cancer, hoping it might be simpler something like hairballs, URI? But he doesn't have any other symptoms, pretty active and eating well.