First of all it’s really really awesome we have finally a way to translate fields.
Because I’ve waited for it I’ve already tried it and found that translations are not showing.
I did some digging and it looks like the strings are properly translated, but not assigned to the field.
In file /api/api-field.php around line 180 there is acf_translate_keys( $field, acf_get_setting('l10n_field') );
The acf_translate_keys returns translated string, but it’s not assigned to anything.
I’ve changed it to $field = acf_translate_keys( $field, acf_get_setting('l10n_field') );
and it’s working as expected
Same goes for group names in /api/api-field-group.php line 74. I’ve changed:
acf_translate_keys( $field_group, acf_get_setting('l10n_field_group') );
to
$field_group = acf_translate_keys( $field_group, acf_get_setting('l10n_field_group') );
And with that everything works as expected so far.
EDIT:
Ok, the only thing I can’t seem to get working is the “label” for the flexible content layouts. Each label inside the layouts are with those changes translated, except the title of that layout. I tried to find where could be a problem but it looks like acf_translate_keys() i never called for this one.