What is the most universal word or phrase?

Ok is the most universal, everyone can understand it.

I think the most universal word which is found in many languages is  "Amen"

"you" and "I" is the most universal word used 

Hello! How are you? The greeting formulas are the most universal words/phrases in all world human languages, perhaps 

i think thanks is universal phrase... 

I think , "OK" or "sawa"in arabic