Asklemmy

Well, in German we say "bitte" or "gern geschehen", which is close to the "welcome". Of course, people can and do also say "kein Problem". I guess in my experience it depends on how I feel about the task and the person I did it for.

It varies regionally. While "you're welcome" is not at all unusual in the UK, it's nowhere near as expected and standard as it is in the US.

I often hear "not at all" as a response, just like "de nada". It's also common in the UK not to respond at all, as the thanks are expected.

Swedish says "varsågod" (literally something like "be so good"). Finnish developed social courtesies relatively late, and so translated the Swedish literally to "ole hyvä". Russian on the other hand uses пожалуйста (pozhaluysta). Don't know exactly where this last word came from, but nowadays it's used the same way as "please" as in "please, no thanks needed"

Can I please (pozhaluysta) have this cake?

Yes, here you go.

Thank you!

Please (pozhaluysta)

Thai/Lao is ไม่เป็นไร/ບໍ່​ເປັນ​ຫຍັງ translated as (implied subject “it”) + negation marker + copula + anything or “it’s nothing”