You could advertise on technology websites, etc. With bitcojntalk you can use signature campaigns, buy advertising space from the forum (that appears between the first post and first reply to a topic).
I'd suggest requesting translators either in the marketplace services section or in the local boards - both should work fine.
Thanks for the reply. I also see various topics like promotion in twitter, telegram, etc. I don't fully understand how it works. For example if there is a telegram channel what does the promoter do? Does the promoter become a moderator and responsible for adding as much people in the channel as possible?