Insider's Guide to the DR
To the Dominicans, most foreigners are referred to as 'Gringos', or 'Gringas' in the female context. This shouldn't be taken as an insult, just a friendly greeting. There is even a Dominican newspaper called the 'Gringo Times'.
Although many locals may speak some English, German or French, most speak Spanish only. The more effort you put into speaking Spanish while you are here, the more you will get out of your interaction with them. Even if you only know a few words, making the effort is what counts. Don't be afraid to make mistakes, Dominicans are usually pretty patient and most cases will be pleased to assist and help correct your grammar.
If you are staying in an all-inclusive resort, and you have the time, you will find so much more if you venture outside of the resort. The island of Hispaniola (of which the Dominican Republic is two-thirds, Haiti one third) contains a wide diversity of geographical and floral aspects, mountains, lakes, triopical forests, waterfalls. You can either take an organised tour, or for the adventurous, make your own arrangements. There are plenty of tour guides and taxi drivers who will be more than happy to take you on a personalised tour to see whatever you want to see. The price for this will be much lower than you would expect at home, and you may even end up making some new friends!