bug with rammus I can not hear any sound

There is no sound to it, that's all there is to it.

If you are talking about his emotes, then you should not be hearing anything. Rammus doesn't say anything during any of his emotes, the most notable being his laugh, which is one of the few, if not the only, laugh in the game that is purely visual, instead of having both audio and visual.

If you can't hear any of his other sound effects like that from his abilities or his auto attacks, then it definitely is a bug.