Every text enclosed by translation marks ## will be considered a language constant, and if translation of this constant is added to the language file it will be automatically translated for users using this language.
Example:
Let's say we want to add custom signature to merchant emails that are sent to affiliates and we want this signature to be automatically translated according to preferred language of the affiliate. First let's add a new language constant ##signature## to the email template.
(As you can see there are some phrases that are supposed to be automatically translated already defined in email templates by default.)
Now edit your language file and add new translation for source message signature to your language file. After it's added to your language files this signature phrase will be automatically translated for users based on your custom translations of this phrase defined in your language files.
NOTE: When editing or adding new translations keep in mind that all translations are case sensitive!