mouth off (verb)

1. As they strolled hand in hand through the park, he couldn't help but mouth off about his undying love for her.

2. In the intergalactic battle, the captain of the spaceship mouthed off inspiring speeches to rally his crew.

3. At the glamorous fashion show, the commentator mouthed off about the intricate details of the latest designer collection.

4. In the animated series, the protagonist would often mouth off passionate monologues before engaging in epic battles.