"Jokes" are always difficult to understand.
A joke alone could be misunderstood.
And the "humor" differs from person to person and country to country.
I am sure you wouldn't understand my German jokes.
I am from Bavaria (special idiom) when I made MY Bavarian jokes with my Prussian colleagues (special idiom) they did'nt understand and got sometimes very angry about.
Both speaking German!
I had to explain the sense, so it was fine.