normalization of lang tags in text query

It would be helpful if there was an option in the assembler option of the text query to normalize the lang tags of the query and the lucene indexes. In the current state, a literal with a lang tag zh-Hant will not be found by a search on zh-hant. I understand that in some cases the distinction might be important (although I have a hard time finding a real life use case), but I think in many cases it's helpful to ignore the case of the lang tag.