I finally found it - a Shuzo Oshimi manga that doesn't have weird hangups about women! It's a miracle!
SHINO CAN'T SAY HER NAME (Shino-chan wa Jibun no Namae ga Ienai), by Shuzo Oshimi. First published in 2011 and first published in North America in 2021.
PLOT:
Shino has long suffered from a stutter, one that tends to stop up her speech entirely in moments of stress (which only serve to make them more stressful). It strikes during her class introduction, which only leads to mockery and alienation. Then Shino meets Kayo, a rough-around-the-edges classmate who loves music but can't sing to save her life. They form a tentative friendship, but can it survive a school festival music performance, a classmate with a crush, and Shino's own anxieties?
