ליטװיש יידיש
Litvish Yiddish
Crown Heights +1Yiddish, the principal mother tongue of European (or Ashkenazi) Jews, has likely been spoken in the city since the 17th century, but large waves of speakers first arrived in the 19th century: initially German Jews, some of whom apparently still used now largely moribund Western Yiddish, and later large numbers of speakers of all varieties of Eastern Yiddish from across Yiddish-speaking Eastern Europe. By the early 20th century, New York City had become the largest Yiddish-speaking center in the world, with mass media, theater, and other institutions to match.
L
itvish Yiddish, based on northeastern Yiddish varieties, has been maintained to a degree by the Lubavitch community in Crown Heights and by other Haredi/Yeshivish with roots in Lithuania and the surrounding region. Lakewood, New Jersey, with one of the world's largest yeshivas, is a significant center of scholarship following to a degree in the Litvish tradition, and one person reports its use in the Bais Hatalmud community of Bensonhurst.
Note that the language above may be used throughout the New York area — this is just one significant site.