Mishnayos Yevamos Perek 14 Mishnah 7

If two brothers, one of whom is a deaf-mute and the other one halakhically competent, were married to two unrelated, halakhically competent women, and the deaf-mute married to the halakhically competent woman died, what should the halakhically competent brother married to the halakhically competent woman do? He either performs ḥalitza or enters into levirate marriage. If the halakhically competent brother married to the halakhically competent woman died, what should the deaf-mute brother married to the other halakhically competent woman do? He cannot perform ḥalitza with her, as he is a deaf-mute. Rather, he marries her, and he may never divorce her, as sexual intercourse between a yavam and his yevama creates a valid marriage that cannot be broken by the bill of divorce of a deaf-mute.

שְׁנֵי אַחִים, אֶחָד חֵרֵשׁ וְאֶחָד פִּקֵּחַ, נְשׂוּאִים לִשְׁתֵּי נָכְרִיּוֹת פִּקְחוֹת, מֵת חֵרֵשׁ בַּעַל פִּקַּחַת, מַה יַּעֲשֶׂה פִקֵּחַ בַּעַל פִּקַּחַת, אוֹ חוֹלֵץ אוֹ מְיַבֵּם. מֵת פִּקֵּחַ בַּעַל פִּקַּחַת, מַה יַעֲשֶׂה חֵרֵשׁ בַּעַל פִּקַּחַת, כּוֹנֵס, וְאֵינוֹ מוֹצִיא לְעוֹלָם.