From the Nica Dispatch...

Nicaraguan Spanish: Speak like a native! takes an in-depth look at 200 of the most common expressions and teaches you some history and culture on the way. As such, it is not a basic Spanish manual; rather, it focuses on making your Spanish, however much you may know, more Nicaraguan.
http://www.nicaraguadispatch.com/new...peak-nica/6332

Amazon.com http://www.amazon.com/Nicaraguan-Spa...89&camp=211189

Available on Kindle! (I just ordered it)