Chronometer

Chronometer
 

Do we say use a chronometer?
I´m gonna use a chronometer to control your speaking time.

"Your speaking time will be timed." (?)

timed :good:
clocked

(It's very uncommon to hear chronometer.)

I'm gonna use my watch (a stop watch, a timer) to limit your speaking time.

In the US the more common word is "timer", short for "countdown timer": a device that you can set up to wait for a specific interval of time to pass before producing an audible or visual signal. The time interval is measured from a starting signal. In contrast, an "alarm clock" is set to produce an audible or visual signal at a named moment in time.

And what Rusty said.

Thanks, it´s impossible to figure out how to say new things, things that you haven't heard before. In Spanish we would say to control the time period.