Don’t and Doesn’t

The negative form of do is do not. In spoken English it is common to use the contracted form of do not which is don’t.

I do not like sport.
I don’t like sport.

The negative form of does is does not. Also, in spoken English we usually use the contracted form of does not which is doesn’t.

He does not like sport.
He does’t like sport.

The negative form of did is did not or when speaking, didn’t.

I did not know you were coming.
I didn’t know you were coming.