The subtitles are basically adjusted every frame but you don't necessarily have to do it by hand. You can for example generate motion data with Blender or Mocha and import that into Aegisub (the software that is used to create the subtitle files).

https://unanimated.github.io/ts/ts-mocha.htm

https://github.com/TypesettingTools/Aegisub-Motion/wiki/Appl...