It is also possible to identify the individual responsible for the regularization, and, using the choice and orig elements, to provide both the original and regularized readings:
<q>Please <choice> <reg resp="#LB">knock</reg> <orig>cnk</orig> </choice> if an <choice> <reg>answer</reg> <orig>nsr</orig> </choice> is <choice> <reg>required</reg> <orig>reqd</orig> </choice></q>