Following our post on Facebook, here is a list of suggested ways to say “thank you” in Finnish
Kiitos – the de facto thank you
Kiitosta – the singular partitive of kiitos also used as thank you
Kiitti – a shortened form of kiitos
Kiitoksia (also Paljon kiitoksia) – the plural partitive of kiitos meaning (Many) thanks
Kiitokset – plural form of kiitos, meaning thanks
Suurkiitokset – big thanks
Kiitän (or kiitämme) – from the verb kiittää (to thank), meaning I thank (or we thank)
Tattis (variation: tattista vaan) – slang from Swedish (http://urbaanisanakirja.com/word/tattis)
Tänks – slang obviously borrowed from English
Feel free to comment on this post if you have more suggestions…