In Czech even no can be yes! I have met tourists in Prague who have had problems with czech: "nó" and "fak jó". I hope I can help to prevent some misunderstandings posting this message. Czech word for yes is "ano" and short version (yeah) is "no". Some people even pick up phone and first say "no". Some foreigners are offended when they hear "fak jó", which sound very nasty in English. But in Czech it expres: "really?" The word "fak" is slang for fact and "jo" is slang for yes. Staying in Czechia you may run into these words, but do not try to use them. People would think you speak English! Good luck!
Indeed, Czechs quite often say "no" /no/ to express consent. It's actually more like "well", but it often practically replaces "yes". In any case, the word is an informal one. As regards "fakt", which really sounds like 'fucked' (sorry), the paradox is, it basically is a Czech pronunciation of the English word "fact". Hence the meaning of the word; perhaps a bit more like "really" in Czech. Even most Czechs who can speak English don't realize this or can't avoid using the word while speaking Czech. As a Czech proverb goes, "Habit is an iron shirt." (literal translation). Again, the word is an informal one. Jirka
