Just a hint if not known already: Have a look at the texts provided at the current PTS 7.3 (English) here:
https://raw.githubusercontent.com/es...tedstrings.lua
You should be able to reuse some texts via GetString(SI_...) constants and they should be translated to ES by vanilla ESO then in the future.
Like "Settings" -> SI_GAME_MENU_SETTINGS
(described here:
https://wiki.esoui.com/How_to_add_lo...g_Translations)
Works for all officially languages and you do not need to translate de, en, fr, ru and es manually in your addon then, just put
ESOFB_SETTINGS_SETTINGS = GetString(SI_GAME_MENU_SETTINGS) in your first loaded file (I assume that's en.lua) and it will be provided for all supported official languages that way.
Edit
Additional benefit: Custom languages added like PT or BR or IT ... will also use these SI constants for vanilla texts and thus your UI will automatically translate those as well even if you do not provide an extra pt.lua language file in your addon -> will load via the first loaded/default e.g. en.lua file then,
as long as you use the txt file of your addon to load the language files via the $(language) placeholder (like described here:
https://wiki.esoui.com/How_to_add_localization_support)