thanks for your previous answers, they helped me. But now I'm little lost in sorting (in registers -- index etc.). I know there is file sort-lan.mkii with sorting rules for czech language, but Context is not sorting by these rules (letter ch is not recognized). So, is there some way how to use it? (I can add it to context.mkii and generate format again, but I'm not sure, it was supposed to be this way). Also mkiv version of this file doesn't exist, but sort-lan.lua does. So how is it handled in MkIV?