Quite recently I have noticed that most Bavarian verbs can become theoretical epistemic modal. What I mean by that is that you can take any verb, e.g. "[i] ko" - "[I] can", and turn it into it's theoretical form "[i] kand" - "[I] could". The special thing about Bavarian though is that you can make it even more theoretical and turn it into "[i] kandad" which could be translated to "[I] could (in theory)". Another example is "[i] muas" - "[I] must/need to" turning to "[i] miassd" - "[I] would need to" and finally "[i] miassad" - "[I] would need to (in theory)".
Are there other languages that have this "two tier system"? I'm especially interested in other Germanic languages.
I am sorry if I misused any technical term. I just got into studying them, so if they are misused, please tell so I can fix it.