I had to laugh - the guy that cuts my grass is Mexican. He actually HAS limited English skills. In his case, I use Latin to communicate, somehow he gets the message. ...A little Latin goes a long way - hardly a dead language.
Strange.
I did my final year (out of 6) of Latin at the Colegio Americano in Quito. I was the only Gringo in the class, which was famous for being among the most tedious and difficult of all the classes. Even for the kids who had been taking Latin for the previous five years, it was not easy and knowing Spanish did not make it easier.
Using Latin to speak to Spanish speakers is sort of like those comic-strip tourists who add an -a or an -o to the end of English words to make them sound like Spanish. There are enough similar words to sometimes make a point, but you can't really communicate that way.