To add a field as an extra column, right-click on any column header in the files list and select Columns...
In the next dialogue click on the New button
Enter a column heading e.g.
in the field Value enter the field name or select from the list opened with the arrow button - in this case %language%
In the field Field enter the name of the target field - in this case %language%
You can do the same for any other field, e.g. UNSYNCEDLYRICS.
You may also append the tag panel. Check Tools>Options>Tag Panel>New for this.