GhostAnjo wrote:Most of the time he’ll only whistle the same loud tune over and over again, which sounds like he’s whistling for a dog . He does this when I leave the room ,or when people are talking to each over from across different rooms , or someone other than me enters and leaves the room with me in the room or not, or he’ll do it at random inside and outside of his cage, mainly when he’s not getting attention at that moment but he’ll sometimes do it when he is getting attention. I can sometimes get him to stop when I cover his cage.
Actually from what you've said above it sounds like his whistle is his "contact call." It's completely natural for a bird to call out to its "flock" when they are out of sight. I have owned several different species of bird in my life and they have all used contact calls. If you don't like the whistling you can encourage it to stop by not responding to it but it's likely that he will replace it with a different contact call.
Your best bet is probably for you to choose what you'd like his contact call to be and then teach it to him by using it when you are out of his sight.
For example, my brown headed parrot Jimmy has a natural contact call he makes but I always respond from the other room with "Jimmy! Jimmy!" He still makes his own contact call when I leave the room but I'd say 85% of the time he now says "Jimmy" instead.
GhostAnjo wrote:Occasionally he’ll imitate the squeaking of dog toys, as well as make tooting, and mumbling sounds that make it seem like he’s trying to talk but he’s been doing that since one week after I got him.
If he's mumbling he's trying to work out words that he's hearing. I agree with Liz: he's storing up words and will blurt out something one day when you least expect it.
Brfussne also makes an excellent point about the microwave. Both my brown headed parrot and my GCC imitate the microwave and oven timer beep; my brown head's imitation in particular is extremely loud, shrill, and high-pitched. I don't mind it, really, but if you don't want to hear it from your CAG definitely take steps to prevent it.
I'm not sure how well recordings work but my personal opinion is that talking to your bird in context is the best way to encourage speech. Choose certain words that you will always use for certain actions, such as "bye bye" when you leave the room or house or "hi" when you enter a room, etc.---whatever you want him to say. If you're interacting with him tell him what you're going to do before you do it ("Do you want a bath? Let's give you a bath").