Hmmm, myself and every instructor I ever worked with or met at FRG were fluent in this country's predominant language...
Unless there's been a startling influx of foreigners in central Long Island in the last three years, I think I can say with some confidence that you would do fine at FRG or ISP (though I don't know why you'd go all the way out to Islip when Farmingdale is much, much closer).
Now as for the rental rates on a 172... "Gouged" is not an incorrect assessment. Like I said, anywhere in the NYC area is going to be expensive, especially since their insurance went up even more quickly than the Twin Towers went down. I think that Nassau Flyers will get you for $85/hr in a 172, but they have 152's and 4 types of Piper singles to choose from, too.
In any case, if you don't have a car, Pennsylvania is out. If you DO, it's your choice if you want to drive twice as far as any of the airports local to NYC to save a few dollars on rental fees (instead spending that money on gas, and depending upon how you get to Bucks County, tolls too).