As I learn different languages, I start to realize the coincidental similarities between words from around the world.
Compare the Portuguese "obrigado" and Japanese "arigatou (有り難う)".
They don't just sound the same, there's a connection with these two words which is deeper than "thank you".
The word "obrigado" means (roughly) "(in the past) obligated". In Japanese, the words for "arigatou" means something similar.
有り - (roughly) for there to be
難う - difficulties
therefore, 有り難う means something like "there were difficulties" and what do you do when you "obligate" someone to do something? You cause them "difficulties".
Here's another: Japanese's Waraji (草鞋) and Mexican Spanish's Huarache. They sound extremely similar and they both mean sandals.
Also, Mandarin Chinese's (的pronounced "duh") and Portuguese's and Italian's "da". They both are used for possession.
Another common thing is using the vowel "o" on the word "I" for different languages.
All of the following mean I/me:
Mandarin Chinese: wo