We've used Rosetta Stone in a number of languages over the past few years. Klaus tried to use it for homeschooling Japanese three years ago. It was a failure. We couldn't tell what he had completed and it seemed he was making no progress, even after spending several hours. Because of that, and the expense, and the fact that they didn't offer Irish, we tried Pimsleur and a number of other language learning products for Xavier last year.
They weren't very helpful, either.
Now, it seems, Rosetta Stone has realized that with some parental/teacher support, they can make their product well worth the expense. The homeschool edition offers reports for parents "suitable for adding to an education portfolio." All of their languages seem to be offered in this new homeschool version, including Irish.
Click here for an excellent, detailed explanation of what each package offers, courtesy of freelanguage.org.
Rosetta Stone itself is offering a $100 off deal, but you can also check out the group buy from the Homeschool Buyer's Co-op.