Speaking under your breath involves very low volume, making it hard for others to hear.

Low Volume

Often implies discreet disagreement or disapproval without making it obvious to everyone.

Discreet Disapproval

Can be used for self-reminders or self-motivation without intending others to hear.

Used to communicate thoughts or feelings meant to stay private or unnoticed.

Can convey sarcasm or irony to oneself or to someone close by without being overt.

Helps avoid drawing attention or interrupting while still expressing an opinion.