What is Shemichah?
Rashi, Radak citing Targum Yonasan: It is a thick wool garment.
Radak, citing Vayikra Rabah 23:10 #1: It is a scarf.
Radak, citing Vayikra Rabah 23:10 #2: It is a silk garment.
Radak, citing Reish Lakish (in Vayikra Rabah 23:10): We do not find such a Kli in Tanach 1 ! We expound it Shmi Koh - My name 2 testifies that this Rasha did not touch her. 3 This contradicts the opinion that he had Bi'ah with her (Radak 5:27).
Imrei Yosher: Ba'Shemichah (with a Patach under the Beis) implies that it is known from elsewhere.
'Ya'el' is like Kah (Yud-Kei, but without the Hei) Kel (but there is an Ayin in place of the Aleph). (PF)
Maharzu: It says "Shachav Bein Ragleha " (5:27)! Rather, Hashem's name testifies that she did not enjoy the act at all. She intended only to save Yisrael.