Drupal 8/9 TMGMT Supported Source Languages

In Drupal 8/9, we use the TMGMT module as our base for translation integration. Therefore, the behavior is the same as TMGMT. By default (strongly recommended), you can only have one source language for a site, which should be the site’s default language.

There is a workaround in case you need something different, however, it's better if you can avoid doing this:

1. Choose the "Cart" option in TMGMT from where you select a source language for a Job.
2. Create new instances of Smartling provider from the Providers tab. One provider for one source language.
3. Get new credentials for the project from the Smartling Dashboard. You would need new credentials for each source language.
4. Configure each new provider with proper credentials.
5. When submitting the content, be careful not to confuse which Smartling provider to use for this translation.
6. Develop your translation plan, as you may get tree-like translation dependencies that are difficult to manage.