Last year, Smilegate said that Lost Ark will someday arrive to EU and NA but since then, nothing has been said about the expansion and by the looks of it, Lost Ark will not have a Western release anytime soon. Korean website The Bell reports that Smilegate do not have any plans for EU and NA release at the moment and are focused on the existing versions and the upcoming Japanese release.
I find this pretty disappointing since the game has always looked pretty promising but, according to the article, it's been losing popularity in Korea due to a poor end game and bad monetisation model so maybe it's not a huge loss. I do think it's funny they call out localisation being one of the main reasons while they're making a Japanese version and already have a Russian one (that's apparently the best way for English speakers to play right now). I think this is one of those situations where EU and NA aren't going to get it until it's dead in Korea.Apparently, the localisation is the biggest issue for the developer as it takes a lot of time to translate all subtitles and record new, English voices. On top of that, the devs are pretty busy with the Japanese version, which basically means that you can forget about Lost Ark EU/NA servers in 2020.