The point of it …
1. Different languages sometimes require specific fonts.
2. Languages vary considerably in their preferences regarding sorting order. Spanish, for example, uses this order: A,B,C,CH,D,E,F,G,H,I,J,K,L,LL,M,N,Ñ,O,P,Q,R,S,T,U,V,W,X,Y,Z. And accented characters are by default treated as equivalent to their unaccented counterparts in some languages (so, in French we get donne, donné, données, donner, donnez, etc.) but in other languages accented characters are not considered to be related to the unaccented form in this way (in Czech we get cesta .. cas .. hre .. chodník ..)
Sorting is handled using Microsoft routines. If you process texts in a language which Microsoft haven't got right, you should still see word-lists in a consistent order.
Note that case-sensitive means that Mother will come after mother (not before apple or after zebra).
It is important to understand that a comparison of two word-lists (e.g. in KeyWords) relies on sort order to get satisfactory results -- you will get strange results in this if you are comparing 2 word-lists which have been declared to be in different languages.
Choose the language for the text you're analysing in the Controller under Language Settings.
If the list which opens up where the red arrow shows doesn't include your language, press Edit languages.
The language and character set must be compatible, e.g. English is compatible with Windows Western (1252), DOS Multilingual (850).
You can view word lists, concordances, etc. in different languages at the same time.