sharke
I'm not sure if you even need to include spelling mistakes for SEO purposes these days, because Google automatically corrects them when you search. For example, if I search for "Justin Bieber is a bufoon" Google delivers me results for "Justin Bieber is a buffoon" instead. It works for brand names as well, e.g. "Kodac Cameras" is automatically changed to "Kodak Cameras." Might want to look into whether or not Google is automatically correcting the misspellings you're including as hidden content, because if it is then there is no need to get yourself potentially penalized by hiding stuff.
I found it's also very useful for those using the search function
inside the website.