Many times in Halachah we see that talking is considered a Hefsek and we are required to remain silent and if we spoke we may be required to repeat or redo something.
Is writing or texting the same as speaking in this regard and considered a Hafsek or not?
Yes.
Do you mind providing a source for that? It seems to me to be difficult to understand. (unless you are coming from the fact that writing my be considered a kiyum of the mitzvah of talmud torah for birchas hatorah?)
It depends on the Mitzvah and how the hefsek may undermine the Mitzvah.