Bloomberg is an idiot when coming to illegal immigration. He's desperate because he's not going to get the votes from the traditional republican base.
The vast majority of New York's immigrants are legal. However, I think Bloomberg is wasting money. In the past it was not uncommon to come across immigrants who had been here for decades and still didn't speak English, even second generation families spoke no English. My co-worker’s grandmother who was born here still spoke only German when she died at the age of 89 last year. You'll be hard pressed to find an immigrant who has been here for decades and still doesn't speak English nowadays. I don't know if a second generation immigrant who doesn't speak English even exists anymore. As a country, we are doing a good job of assimilating immigrants. This is just a publicity stunt on Bloomberg's part.