What word root term is some television commercials are aggravating because the speakers talk rapidly?

The word root that relates to rapid speech in television commercials is "tachy-".

Here's why:

* Tachylalia is a medical term for rapid speech.

* Tachycardia refers to a rapid heartbeat.

* Tachymeter is a device used to measure speed.

So, the root "tachy-" signifies speed or rapidness, making it the relevant term for describing fast-talking commercials.