As a traveler I think the most important phrase is “Thank you.” That was what I learned to say before each country we traveled to. Even if you can't speak the local language and talk in English or gestures, it is nice to be able to thank someone in their native language. Second most important for me is “I'm sorry” or “excuse me”. That is very useful when on crowded buses or trains and you have to push by someone to get off. Third is probably “where is the bathroom?” or simply “toilet?” which gets the message across.
Anyway, here is how to say “Thank you”, in every country we visited, at least how it sounded to me. Please don't get too offended if I mangled your native language, I was trying 🙂 :
Taiwan (mandarin), China: Shi-shi
Korea: Gamsameeda
Egypt (Arabic): Shockram
Zurich – Switzerland, Vienna – Austria (German): Danke
Geneva – Switzerland (French), France: Merci
Spain: Gracias
Italy, Vatican City: Gratzie
Hungary: Kusonome
Czech Republic: Dekuji
Poland: Dziekuji (very similar to Czech)
Norway: Takk (pronounced like talk)
Denmark: Tack (like tact)
Iceland: this is the one I didn't learn. Supposedly it is similar to Danish (tack) but they add several syllables to differentiate from Denmark. Just saying “tack” is frowned upon, so I went with “Thank you” which everyone understood.
Canada, U.S.A.: Thanks.
-David