"Many Czechs do not consider Slovak a foreign language."
Translation:Mnoho Čechů nepovažuje slovenštinu za cizí jazyk.
Can someone explain why the verb is in singular and not plural? Is it an exception or is there a rule for it?
Because Czech works like that, really. "Mnoho" is considered gramatically singular for verb agreement. Not much more can be said.
English is different, it has a lot, that means one lot, and still uses plural (a lot of things are). That is weird for me coming from Czech.