Just say 'Whale Oil Beef Hooked' fast. 
And after that, you need to recite the magical incantation. "Owa... Tajur... Kiam."
So in your opinion, is it worth the money over all other language tools? What makes Rosetta Stone special?
I haven't tried any other language software (not even sure whether there is any; I would assume there is), so my only basis for comparison is older technologies such as audio recordings and those whatchacallits. Books. That's not really a fair comparison, of course, but since it's the only one I can offer, here it is:
Yes, Rosetta Stone blows the doors off of using books or instructional tapes or CDs. Rosetta Stone has pronunciation practice, for example, where you listen to a word or sentence and are asked to repeat it -- the software then tells you how good your pronunciation is. If you're completely off, you get a "wah wah" sound, whereas if you're mostly close and mispronouncing only one word, that word will appear in gray to tell you you need to practice it some more.
Rosetta Stone is also web-based, so if for any reason you ever want or need to do the lessons on a different computer, you don't have to have the software installed. Rosetta Stone also offers free apps for your Android or iOS device. All of this is synchronized on Rosetta Stone's servers, so if you do three lessons on your Droid, then go home and continue studying on your laptop, you will automatically be sent to the next lesson after the one you were working on on your Droid.
Rosetta Stone offers one-on-one audio/video instruction with native speakers -- a certain number of lessons are included with the software, and additional sessions are available at an additional charge. There's also some community stuff as well -- for example, in a couple of weeks, there's going to be an Irish "game night" where you practice your language skills with other people who are using the same software. I haven't tried any of this stuff yet but plan to do so after some more practice.
The big downside, as has already been mentioned, is that you will pay thru the snout for all of this. I got the full Irish course on sale thru Groupon, as I said, and even with the discount, it was about $330. Other languages are even more expensive. Irish currently offers only levels 1, 2, and 3. Other languages, such as Spanish, go to level 5, and Spanish is about $500. There are alternatives that cost a bit less -- for example, if you want to just buy twelve months of online access to Spanish lessons instead of springing for the actual software, you'll pay less. And they do offer interest-free financing, so that helps as well. Even so, though, for that kind of money, I wouldn't recommend it unless it's something you're sure you'll be at least somewhat serious about.
Their web site offers a free demo, so you can get an idea how it works if you're really interested.
http://www.rosettastone.com/demo