DF party list language column

Exactly what does it mean?

http://i.imgur.com/PUHZ0ym.jpg

The first row in each of the above is myself. In both cases I play using the Japanese client, and join with J and E activated.

It seems that the underscore represents game client language, and highlights show which language option was activated.

But then what does it means when none of the languages are highlighted? Anyone have an idea?

I think the letter doesn't light up if they are part of a group you have pre-made, as they technically didn't select a language to queue up with.