tatinana

Hello my friends I'm new to the forum and I join the forum to get help. I have a grey for 6 years and I had him since he was a baby. He doesn't talk as much as he used to. Of all the words that he used to pronounce he is only saying 5 of them now. I will like to know if he's too old to learn any more and if he's not how can I teach him new words? I would also like to know how can I tell if he's paying attention to me while I'm talking to him. All help will be appreciated tanks.