A joke that is often made about Japanese is that they don’t have a word for no but just say hai in an uncertain manner. They actually do though: ie (pronounced ee e).
Now one of the very few things I’ve learnt with my very limited Chinese* is that the Chinese actually *don’t* really have a separate word for no in fact saying bu shi which translates as “negative yes”. Of course as unlike Japanese, Chinese is tonal which means it is impossible to just say yes directly in an uncertain manner as it could well mean something entirely different. Maybe at one time the Chinese had a proper word for no, it’d be an interesting thing to find out.
* this means I’ve just about made it onto really tough words like yes for example :p.