Hello Danara, You can almost use the same sentence with just a little modification "You are talking so slowly, that sometimes I forget the beginning of the sentence!" Best wishes Bob

No, this isn't correct. There are lots of ways of expressing what you seem to be suggesting; for example: 'You are talking so slowly that sometimes by the time you arrive at the end of a sentence, I have forgotten what you said at the beginning (of it).' But there are lots of variations.