The smallest time unit in practice

How long is a blink of an eye?

Roughly speaking, the length of a moment is 0.1 second (100 milliseconds).

The discrete sound that a human can hear and distinguish is 100 milliseconds.

The time required to retain and become aware of the firing patterns of neurons in the brain is 100 milliseconds.

A single phoneme of the most commonly used word daily in English, such as the, to, it, and you, is 100 milliseconds.

A single complete act that contains a series of those milliseconds is a speech line.