Oh, lol. Yeah, Slovak sign language is pretty popular... in fact, there is a party club for deaf in Bratislava.
Went there once. And Slovak and Czech sign languages are not SAME at all.
When i attempted to write in Czech, they were confused after some successful tries. Then they wrote in Slovak, I was confused as well after series of clear communication. This led to tensions actually, lol, during our height of drunken hours. HUGE cultural shock for me.
I never went back to there again after that night. Besides, most of them were pretty young anyway, all they want is just to party instead of talk. I was much older and umm I generally do like talk rather than hedonist party... but anyways.
This reminds me of the setting situation in my encounter with Moravian dialect (not sign language), actually. I know, this probably is getting complicated for you to understand, but I can't quite explain it better myself. Moravia is southeast of Czech lands, and maybe few parts of southwest Slovakia, not too sure about that one. I'm pretty confident that mostly it is in CR.
That video actually isn't bad