take away the child feedback of "no-no" for a wring answer.
"Try again" would be more appropriate. I just feel that a 2 year old doesn't need to hear no every time they get a wrong answer. It's not very encouraging.
My daughter spent quite some time yesterday making incorrect matches just to giggle at the way it is said, often saying it herself before finishing the pair. It's one of the only things that keep her from exiting to another game instantly every time it comes up.
Comparing the fun way of delivering the feedback of "no-no" against the phrase "Try again", "no-no" has less impact to the child. The 3 letters "T R Y" has serious damage in the long term preventing the child giving their best. If "no-no" where to be replace, it should be something that is more encouraging / empowering, like "Good. You can do better. Let's do it again."