Is there a connection between פסח (Pesach) and פה (peh / mouth)? They sound similar. Plus, we are commanded to do lots of symbolic eating on the holiday. Has it been written about or discussed? Thank you.
The Arizal (Pri Eitz Chaim, Shaar Mikrah Kodesh, ch. 4) related it to the idea "Peh sach" - "a mouth converses" (as noted by sam in a comment). This can also be connected to the mitzvah of magid.
The Arizal taught that the word "Pesach" is composed of the words peh sach, which means "speaking mouth." When Bnei Yisrael sacrificed the Korban Pesach, they sacrificed their speech to Hashem - by refraining from uttering forbidden words of lashon hara, anger and contention. Accordingly, the Korban Pesach was an essential catalyst of the Exodus from Egypt. By sacrificing their peh sach, their "speaking mouths", they proved their greatness and their worthiness to be redeemed.
Nesivos Shalom comments that Sichon (from the word siach, as in speech) is melech haEmoree, as in amira, speaking. Sichon is spelled סחון
Talmud Brachos uses sach with a samech ches to mean speak תלמוד בבלי מסכת ברכות דף נא/א אמר רבי ישמעאל בן אלישע שלשה דברים סח לי סוריאל שר הפנים
Also see drushei tzlach shabbos hagadol os daled where he says same as arizal