Regimen & Regiment

Without a T – a course of activity, such as a medication or exercise schedule.
With a T – a military unit.

Bough & Bow

-ough – tree branch.
-ow – (v.) bend formally at the waist. (n.) the front end of a ship.
But remember not to confuse these kinds of bows with these kinds of bows!

Pendant & Pendent

With an A – (n.) a hanging ornament, such as a piece of jewelry.
With an E – (adj.) describing something in the act of hanging, like a pendulum.
So, yes, by definition pendants are pendent. I know, it's confusing. And remember not to confuse them with a pennant, either.
Good luck!

Marshal & Martial

John Wayne vs. Ralph Macchio

Die & Dye

Coroner: The victim's lungs appear to be filled with hair coloring.
Detective: What happened to him?
Coroner: He dyed.