Thank you for the answers, Francesco's version works, and Pathoschild's version is for some reason not very happy with the idea of working. :-) That's what I tried previously. Now I have a quite pretty package of Hungarian spellcheck fixes. I am sorry I can't share it with you. :-)
One more question: how can I substitute a new line? \n works in the query, but not in the expression to be substituted.