You probably should add underscores or spaces between the tags, otherwise your file names will be hard to read.
The language tag will only be set, if there is a work related to that track and that work has the language set. For this to work you have to enable Metadata > Use track relationships in options.
Grouping is not populated by Picard. Try the Classical Extras plugin, I think it can fill that tag.
It will append numbers to the filenames.