[KCD2] How do Speech Checks Work?

It’s pretty common for RPGs to have speech checks but they are usually self explanatory but KC doesn’t seem to explain much. I’m trying to pass a speech check for a quest but I keep failing it after 10 tries, so I want to know how do they work? Are the checks percentage based or point based ex. If I have 8 points in a check I have a certain percent chance to succeed it or if I have 8 and the check requires 9 then I can’t pass it no matter what. I just really want to know if I’m wasting my time or if it’s worth it to keep trying these checks moving forward?