In our particular cast, our three year old son has developed a habit of responding "uh-huh" instead of "yes", and "uh-uh" instead of "no".
This makes it really hard to understand which he's saying at times, since they sound so very similar.
I would suspect that the strategies and answers to this issue might be more widely applicable, though, so I'd like to include slang or other grammar issues.
What is the best strategy to correct this and encourage clear, grammaticaly correct speech?