Endangered languages of NYC
The Endangered Language Alliance (ELA) have published a New York City map that denotes languages and dialects (e.g., Sindhi, Ilokano, Ojibwe, etc.) to specific regions within the five Boroughs. The map in the middle of the page is zoomable, but not to a really high resolution (street and block level). They are currently working on an interactive online version.
Not to be confused with the Endangered Alphabets Project, ELA focuses primarily on languages in NYC. Nevertheless, their projects cover a diverse range, such as Jewish, Celtic, Meso-American, and Himalayan linguistic families.