Which New Language Should I Learn: Czech Or Greek?

Greek. There are probably more historical documents written in that language than the other.

There were a number of languages that were used through the centuries and they were called "Intellectual Languages" because whenever a country or empire leads in academics. Students in foreign countries near and far would learn that language in order to travel to that country and study with and read academic works written in it.

There was the Greek langauge, then Latin; and for a period of time: Arabic. Next I think is French, Turkish I think, and the last is German. Of the latter, there are many medical works and scientific journals written in German.

Thanks for the tips. By the way, sorry if I never told you that I was multilingual.

No don't be sorry; I don't expect people to give me all the details about themselves, let alone their personal struggles. to me.

In fact, as an Introvert I do not open up to just anyone.

Ok, I understand