Severus was obviously just as useless a teacher as Harry had claimed -- not that Sirius had ever doubted it. Pronunciation, Sirius could have got from a book. Remus, however, was as helpful as always, and Sirius was pleased to see that he'd made him sweat, this time.
"Well, let's just keep at it, then," he said gamely. "I'd like to be more certain before I go trying it on Faelan -- the poor kid's having a hard enough time with this as it is."
And if he had to practice for a day or two ... well, he would. He might suggest to Remus, though, that it was little point to having Severus stay.