You can change ./qa-include/qa-lang-questions.php (and other qa-lang files). Replace "questions" and "answers" (and any other necessary syntactic changes) with your own sites operative words. On each line, don't change anything to the left of this sign '=>', otherwise you will break things.
To prevent answering questions, go into admin and under permissions, set "ability to answer" questions to some impossibly high quota or other parameter. Good luck.