Most of EET strings are already translated elsewhere. If you are going to create a translation for EET you can use already available translations (if their authors are not against it of course) to save yourself about 90% of work.

First of all notice that all files uses UTF-8 without boom encoding - this is not an error. Mod is design only for EE games, so ANSI encoding is not needed (in fact it crashes the game if text is added to LUA file, even if the file was previously converted with HANDLE_CHARSETS)

No need to translate SoD related strings (chapter text and dialogues) if SoD expansion has not been translated to your language.

2da.tra - CHARSND.2DA strings refers to BG2 soundsets names (which are not named in BG2:EE for some reason) and BG1 default soundsets (other imported sets are already named).
CAMPAIGN.2DA / UI.MENU.LUA section contains lines presented in 'Campaign Select' screen in main menu. For English text I've adopted direct quotes mentioned in intro movies and some marketing slogans found on the internet to describe each campaign. Feel free to write whatever you want there. No need for direct translation.
SAVENAME.2DA section has names used for default saves made at the beginning of each chapter. Vanilla games already makes such saves so refer to them as a base for translation
Worldmap GUI Strings - shorter versions of 'Destination Unreachable' and 'Travelling Hours' strings to make the patch 2.x worldmap less cluttered

chapters.tra - large file that consists of chapter strings existing in BG:EE/SoD/BG2:EE TLK. Original string numbers are mentioned right above the string, so you can simply copy over their content. Most of the time it's a matter of changing the chapter number in the first line. Also as mentioned in the tra file strings @2000024-@2000037 requires additional work with changing the text from narrator perspective to CHARNAME perspective - no need for direct translation - the text should read like CHARNAME was writing it, so feel free to skip some parts and rewrite other bits of original narrator speech (this text is added to USER journal at the beginning of each chapter, no need to edit BG2 strings since they already have chapter start text from the CHARNAME perspective).

dialog.tra + compatibility.tra - for FATESP section use BG2:EE strings as a base (for example: 65010, 65018, 65021, 65016). @1000030 is based on BG2:EE 73956 string but keep in mind that this line should be gender neutral. BDSCHAEL.DLG is a file from vanilla SoD, so you can take base string from SoD TLK.

map_mods_trans.tra - you can find many of these strings translated in BP-BGT Worldmap. Check out string numbers added as comments. Also check out if Miloch's Sword Coast Map Labels mod is available in your language for even more translated strings. ### instead of spaces and area names instead of string numbers are not a mistake. This file is not directly loaded, but EET reads it during installation to get these strings.

prompts.tra - this is a common file with WeiDU constants strings. There are many mods that come with such file, so you can just copy it over without any changes.

setup.tra - strings related to WeiDU installation process (so don't use non-English language letters)

'movies' directory stores voices from the original BG1 movies: BEREGOST, INTRO, NASHKELL, WYVERN. You can send MVE files to WhiteAgnus, if you don't know how to export voice track only. If these 4 movies had not been localized in your country than let us know - in such case English ones will be used during installation.