By default, all dialogue and response prompts will be run through Godot's tr function to provide translations.
Translations in dialogue work slightly differently depending on whether you're using CSV files or PO files to define your translated phrases.
By default Dialogue Manager will try to guess which one you're using based on the files that you have set up in the locale project settings. If a PO file is found it will assume you're using PO files and if not it will fall back to assuming CSV.
You can override this behaviour by setting DialogueManager.translation_source to be one of the values provided by DialogueManager.TranslationSource. None will turn off translations altogether, meaning you'll have to handle them yourself. CSV tells Dialogue Manager that you're using CSVs for translations. PO tells it that you're using PO files for translations. Guess is the default behaviour and will attempt to guess either CSV or PO.
Dialogue lines and response lines can specify a unique ID per line in the form of [ID:SOME_KEY] where "SOME_KEY" is a unique string identifying that line/response.
Static line keys are useful if you need to match up lines with voice acted dialogue.
All .dialogue files are automatically added to the POT Generation list in Project Settings > Localization for them to be included in the general PO template.
You can export translations as CSV from the "Translations" menu in the dialogue editor.
This will find any unique dialogue lines or response prompts and add them to a list. If an ID is specified for the line (eg. [ID:SOME_KEY]) then that will be used as the translation key, otherwise the dialogue/prompt itself will be.
If the target CSV file already exists, it will be merged with.
If you've made changes in the exported CSV to the original lines then you can reimport them from the translations menu.
This will match lines using static keys and replace the dialogue/response content with the text found in the CSV.
Characters' names generally show up in more than just dialogue so it is assumed that they are translated by your game. There is an option to export all character names in a dialogue file to CSV from the Translations menu.
Character names will also be added to the POT Generation list with a context of "dialogue".