Translations in general - understanding the system

[30knees]

I'm trying to properly understand the translation system in tb/PS. Please confirm or correct me in the following:

1. Front office translations: Only theme translation.
2. Back office translations: Only core translations, theme independent.
3. Error message translations: Only core translations, theme independent.
4. Field name translations: Only core translations, theme independent.
5. Installed modules translations: Core and theme translations.
6. PDF translations: Core and theme translations.
7. Email templates translation: Core and theme translations.

The structure is mirrored in the file directory of tb. If I want to translate directly in the files instead of through the backend translation tool, I can do so.

Theme or core?

1-4 only have either theme or core, so choosing which to translate is easy. But 5-7 have files both in the core and in the theme. My understanding (coming from here) is that the core is the default. If I select a theme, all translations from the core will be copied to the theme. So module X in core becomes module X in theme.

Updates

Updates from tb will overwrite the core. If I'd like customised translations, I should make edits in the theme.

[alwayspaws]

@administrators @Global-Moderators This needs clarification, please.

[lesley]

For 5-7 those files will be moved into the theme, so it is best to use the theme translations. All of those files are automatically moved to your theme when you edit translations, so if you edit the core ones, they will always be overwritten.