If seems that display of a fieldgroup by title works, but by id doesn't.
To prevent lots of duplicate field groups and fields in a multi language site, I use language strings for field group names and field labels. Somewhat ugly in the backend, but it works in the frontend, which is the main objective. Unfortunately those language strings don't get converted when displaying them using AA. Can you think of a creative trick to achieve that?
Apologies for asking two, only slightly related questions in one and the same post
How are you outputting the field groups? What syntax?
This one works:
{article}[fieldgroup:foo:description]{/article}
This one does not:
{article}[fieldgroup:1:description]{/article}
Is your second question specific to Articles Anywhere? Are those strings being converted when outputting through Joomla layout?
Yes they are for the most part. Language strings in field group titles and field labels are correctly translated when editing articles in the backend. Field labels are also properly converted in the frontend. Field group titles are not included in the article view, so they don't display at all.
The numerical fieldgroup id issue is solved with that dev version.
When displaying all fields in a group, field label language strings are properly converted. Field group title language strings are not. Maybe a Snippet+Sourcerer combo could provide a usable solution. Unless you have a better idea.