But the Census Bureau’s major surveys do not gauge Spanish proficiency, an equally critical measure for the community of indigenous Latin Americans.

Indeed, for many, not knowing Spanish is as big an impediment as not knowing English. Spanish is the lingua franca among immigrants from Latin America and dominates conversation in neighborhoods like East Harlem; Corona, Queens; and Hunts Point, in the Bronx.

After arriving in New York, most indigenous Latin Americans will learn Spanish before they learn English — if they ever learn English at all. The need has driven demand for Spanish language classes around the city. About a decade ago, the staff at Little Sisters of the Assumption Family Health Service, an organization in East Harlem that provides services to the poor, noticed that an increasing number of the students enrolling in its English as a second language classes were not only indigenous language speakers from Latin America but were also illiterate.

Reasoning that it would be easier to teach the newcomers Spanish, which they were beginning to pick up at home and on the street, the organization turned the English classes into Spanish classes.

Beyond the critical language and literacy instruction the classes provided, they also helped the newcomers build “a much-needed social support network,” said Rosemary Siciliano, head of communications for Little Sisters of the Assumption. In 2012, however, the organization had to cut the program because of budget shortfalls.

For those immigrants who have less than a working knowledge of Spanish and English, even basic services can often remain out of reach. While New York City has a progressive language access policy, it guarantees the provision of interpretation and translation services for city business in only the six most-used non-English languages, which do not include any of the indigenous languages spoken by Latin American immigrants.

Sometimes the struggle of these immigrants is simply to get others to recognize that they are somehow different from the Latin Americans who speak Spanish. They are often mistaken for Spanish speakers because of their nationality and appearance and are addressed in Spanish, but may be too shy or confused to interrupt, advocates said.