BYG Localization: open-source CSV simple localization plugin

Hi all, we wanted to support fan localization for Industries of Titan and found that Unreal’s built-in localization system was not exactly what we wanted. So we made our own, and it’s available on GitHub!

It differs from Unreal’s localization system in a few ways:

  • Only support a single CSV file as the authoritative source for strings.
  • Support creation and maintenance of fan translations.
  • Fallback to primary language if text is missing in a fan translation.
  • Clearer errors when keys are missing in a stringtable.
  • Support multiple localizations for the same language.

Feature Comparison

Feature Unreal Localization BYG Localization
CSV stringtable support :white_check_mark: :white_check_mark:
Add new keys in-editor :white_check_mark: :x:
Reload text on CSV modification :white_check_mark: :white_check_mark:
Support for fan translations :x: :white_check_mark:
Show missing loc keys in-engine :x: :white_check_mark:
Show fallback language text when keys are missing :x: :white_check_mark:
Blueprint code support :white_check_mark: :white_check_mark:
Multiple localizations for same language :question: :white_check_mark:


For this example, we will be using English as the Primary Language, but the system works with using any language as the Primary language.

Create CSV file

We are using English as the primary language for our game so we will create loc_en.csv inside /Content/Localization/, the default localization root directory for localization files.

Hello_World,"Hello world, how are you?",General greeting.,,
Goodbye_World,"See you later!",Shown when quitting the game.,,,

Using Localized Text in Blueprints

After adding the keys to the Stringtable CSV file, choose the entries for all FText properties by:

  1. Click on the drop-down arrow.
  2. Choose the Stringtable ID. BYG Localization defaults to “Game”.
  3. Choose the key

In Blueprint graphs, use GetGameText in BYGLocalizationStatics.

Getting Localized Text in C++

FText ButtonLabelText = UBYGLocalizationStatics::GetGameText( "Hello_World" );

Changing the active locale

FString PathToCSV;
UBYGLocalizationStatics::SetActiveLocalization( PathToCSV );

Stats Window

There is an stats window available in the editor for seeing which localization files have been detected by the system, how many entries they have, the status of those entries etc.

Access it through Window > Developer Tools > BYG Localization Stats.

Customizing Settings

All of the project settings can be modified through Project Settings > Plugins > BYG Localization in the editor, or through Config/DefaultBYGLocalization.ini

Settings include:

  • Localization file directories (default /Localization/)
  • Allowed filetypes (default .csv and .txt)
  • Filename prefix/suffix (default loc_ prefix, no suffix)
  • Forcing quotation marks around all CSV values.

User Experience for Fan Localizers

Creating a new localization

  1. Create a file with the two-character ISO 639-1 language code and optional region suffix. e.g. if the primary file is loc_en.csv and you want to translate the game into French, create a file called loc_fr.csv
  2. Launch the game with the -UpdateLoc flag (create a desktop shortcut).
  3. Your loc_fr.csv file is now populated with all of the primary language

After creating loc_fr.csv and running the game, your CSV file will look like this:

Key SourceString Comment Primary Status
NewGameButtonLabel New Game On main menu, starts new game New Game New Entry
ExitGameButtonLabel Quit Exits the program Quit New Entry

After translation, your CSV file should look like this. You can remove the “New Entry” text from the Status column:

Key SourceString Comment Primary Status
NewGameButtonLabel Nouvelle partie On main menu, starts new game. New Game (blank)
ExitGameButtonLabel Quitter Exits the program. Quit (blank)

Maintaining a localization

As the game is updated, strings will be added, removed or modified.

  • New strings will be shown with the status “New Entry”, and will show up in the Primary Language until they are translated.
  • Modified will be shown with the status “Modified” and what the primary language text was before.
  • Removed strings will be shown with the status “Deprecated”, or automatically removed (depending on the project settings).
Key SourceString Comment Primary Status
NewGameButtonLabel Nouvelle partie On main menu, starts new game. New Game (blank)
ExitGameButtonLabel Quitter On main menu, starts new game. Quit game Modified: Was ‘Quit’
LoadGameButtonLabel Load Game Shows the load game screen. Load Game New Entry



  1. Download the zip or clone the repository to ProjectName/Plugins/BYGLocalization.
  2. Add BYGLocalization to PrivateDependencyModuleNames inside ProjectName.Build.cs.

Unreal Version Support

  • Compiles under Unreal Engine 4.22 up to 5.0EA
  • Tested mostly with 4.25 and 4.26




Future Work

  • Detecting runaway misquoted strings.
  • Allowing multiple stringtables, e.g. loc_en_ui.csv, loc_en_dialog.csv.
  • More tests!
  • Profiling and performance improvements.
  • Improve dir picker, see DirectoryPathStructCustomization


Q) I changed Stringtable Namespace and/or Stringtable ID and now my text is gone!

A) Changing Namespace or Stringtable ID will break all of the FText strings in your Blueprints. You should only set these values once at the start of the project, and not change them.

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Support the 5.0.3 Unreal Version?