Why Is Silence Between Phrases Part of the Music?

Silence between phrases is not empty space. The time between the decay of one phrase and the beginning of the next helps us hear a musical boundary. This is especially clear on the piano because the fingers may have released the keys while the strings are still sounding.

Breathing in performance does not mean mechanically adding extra time. It means hearing when one phrase has genuinely finished. Too much delay breaks the structure; no release at all can turn two phrases into one continuous stream. Written rests provide clear evidence, but harmonic resolution, key release and decay can also create boundaries.

The useful question is not how many seconds a pause lasts, but whether it completes one phrase and gives the next a new direction.

https://www.britannica.com/art/phrase-music