What is the relation between id and sprache and how would you like to present that information in your tree?
QTreeWidgetItem represents a row in a tree and constructing an tree item by passing a string list practically constructs a row with as many columns as items in the string list and passing 2 string lists neither makes sense or is possible.

Is your intention maybe to show a list with 2 columns, id and sprache, respectively?
If so, then you should iterate through the string lists and construct QTreeWidgetItems with one row from 'id' list and another row from 'sprache' list...