I'm from Brazil and we speak Portuguese. We have a lot of false friends.
For exemple Pretend, that means simulate, make believe, assume in English and we have a word Pretender in Portuguese that means intend in English.
I remember the first time I met the word inhabitants in a middle of an English exam. Looks like the word inabitado in Portuguese but they have complete different mean. While inhabitants mean the person who lives in a place the word inabitado in Portuguese mean a place where no one lives. Well I miss that question.
The English word eventually and the Dutch word eventueel
They probably have a similar origin, but eventually means in the end, and the Dutch word eventueel means optionally. It is a so called false friend, in language terms.
To speculate/ speculation
“To speculate” in Russian:
1) means to buy something and then sell in few times higher price ( it was widely used when I was a child due to a total lack of goods in Russian supermarkets)
2) use someone’s feelings or information for own advantages.