Using FIND to determine language of .idx (does it contain string "id: de") doesn't work, yet. So for now it's assumend, the .idx without language attribute is de/DEU/German.
::files without language attribute (i.e. *1080.idx and NOT *1080-eng.idx) will be considered DE for lack of working string search in file
::find would have to be executed in .idx but also .sub has to be renamed accordingly
::therefore the attributeless files be checked and renamed at the end, so it works only for DEU files, assuming they are acctually DEU