What does lol da mean in Welsh?

"Lol da" is not a phrase in Welsh. It appears to be a combination of "lol" (an English internet slang term for "laugh out loud") and "da" (a Welsh word meaning "good" or "well").

It's possible that someone is trying to use a slang term in Welsh or just making a mistake.

If you're interested in learning Welsh, I recommend checking out resources like:

* Duolingo: A free language learning app

* Memrise: Another free language learning app

* BBC Bitesize: A website with language learning materials

* Siop y llyfrau: A website with a large selection of Welsh books

Good luck with your Welsh learning!