City Schools Chancellor Carmen Fariña and Milady Baez, the chief for “English-language learners,” are looking to increase dual-language programs, in which students receive instruction in both English and a second language.

This is bad news for the kids, and the city. I know from personal experience.

Start with the big picture: Multilingualism in a person is a great asset — but a society with no common language is cursed. This holds double for New York, the ultimate city of immigrants.

Without English holding it together, New York would soon cease to work.

As for the kids: Secluding children into separate dual-language enclosures will drive a wedge between immigrants of different nationalities, and make it more difficult for them to become proficient in English.

Here’s how I know.

In 1974, I arrived in Jackson Heights, Queens, at the age of 14 and headed into the eighth grade with the usual apprehensions of a rising seventh-grader — multiplied several times by the fact that I was in a brand-new country and facing a brand-new language.

Little did I know that I was a bit of an experiment. The year I arrived, Congress had made it mandatory for school districts to come up with “innovative” programs to teach children with limited English abilities.

Sure enough, I was thrown into a bilingual class at IS 145 on Northern Boulevard. It took me a couple of days to realize that bilingual was just a title. Instruction was monolingual — all in Spanish.

How was I supposed to learn English in that setting? I asked the other kids in the “bilingual program” how long they’d been there; a few years, many said. Their English-language skills appeared to be about as good as mine — almost nonexistent.

But I had just arrived; they’d been in Queens for years.

My family’s opinion was not sought on the matter. On the contrary, when we tried to convince the school authorities they’d made a mistake, we met nothing but opposition.

It took courage for us to take it upon ourselves to decide that we knew better — but once we made up our minds, fight we did.

My mother, having just arrived and gotten a new job, couldn’t take time off work, so it fell to me, with my broken English, to convince the assistant principal that I needed to be immersed in English, sink or swim.

This middle-aged school official was not sympathetic. He took me into an empty room and proceeded to tell me, in a precise tone, that I was sure to drown.

I still remember him saying, “You’re quite ambitious.” It wasn’t praise, but a clear warning that my hubris was inviting retribution.

Here’s why I remember it so well: It was the first time I had heard the word “quite,” and Spanish has no word . . . quite like it.

But still I understood what the bureaucrat was telling me, and knew that this was the way to learn a new language, by hearing words in context. I stuck to my guns, and was out of the bilingual class in a couple of weeks.

And I didn’t sink.

Flash forward to New York today. According to the city Department of Education itself, 36 percent of ELL students in 2010 had failed a yearly assessment of English-language skills for the previous seven years. Only 30 percent were able to graduate out of the program within three years.

This is not a record of success. This is a record of children being consigned to a bilingual-educational gulag from which many never emerge.

That Mayor de Blasio’s administration wants to expand this failed approach says more about its mindset than about the needs of the city, and of millions of new immigrants like me.

 - Mike Gonzalez is a senior fellow at The Heritage Foundation.