Reference for Berakhot 29:26

ממאי דרבי יוסי היא ודיעבד נמי לא

How can we know that [this quoted Mishnah] is R. Jose's view [and means that the reading of the Megillah by a deaf person] is also invalid post factum ;

Jastrow

Jastrow

Jastrow

Jastrow