Talking to the dumb in your dream indicates that you have experienced unusual hardships in your life, which will qualify you for a higher position. You will get a new position soon.
I dreamed that I suddenly became dumb, but I wanted to open my mouth but couldn't speak, suggesting that there might be a villain trying to slander you, and you couldn't find the reason, which made you unable to move.
I dreamed that I became dumb and then recovered, indicating that I finally defeated the villain.