/stopsound does not stop subtitles from showing

When playing with subtitles enabled, using /stopsound has no effect over the subtitles.

Steps to reproduce (most conveniently):

1. Place a repeating command block with a /stopsound command

2. Make any action that will cause a sound event

3. Observe that subtitles still appear

Expected results:

Sounds affected by the /stopsound command should also not show subtitles

Observed results:

Subtitles show with any sound, even if it was stopped