Hi. The letters do not appear above the buttons, I already played a few years on other servers and the letters and phrases appeared. Is it a bug with an update or configuration?

There's a localization issue that's known with Ragnarok. If you're client doesn't have a localization for the map, then it's possible that the "letters" and "phrases" won't show up.

Humm, ok. How can I solve?

If you're not sure on how to adjust localization or add localization / translation packs, your BEST bet is to simply google setting your localization to English as ARK comes preinstalled with English for both client and server.