I'm trying to find a Weird West novel I read in the US in the mid-to-late '90s. I think it was new at the time and a stand-alone novel.
The story takes place in the United States West, shortly after the Civil War.
The book's world diverged from the real world after a US Civil War battle created a large enough sacrifice that the dead arose and magic reentered the world.
Magic is somewhat random and horrific. Towns in the west survive only if they have a strong magic user as Sheriff. One becomes Sheriff by out-dueling the current one.
The story beings in a small town with a high noon duel for Sheriff. The incumbent wins by carving magic totems which he uses as bullets, but he ends up badly injured. The Sheriff's friend, Our Hero, picks up the action from there.
Our Hero starts as a normal-Joe bystander. He later develops a strong talent where he casts spells by speaking in tongues (in world called babbling or chattering or gibbering or such). At least initially the effects aren't controlled but include teleporting away from a duel/danger.
Another character is General Custer, who Our Hero admires from afar
Until Custer is revealed as the Big Bad and capital-E Evil
It's not related to the Deadlands game or novels, though the genre and timeframe are similar.
It's not any of the examples listed in Wikipedia's Weird West books page