This area is, arguably, the most "Christian," notably Catholic, in Newton (I am not being Anti-Semitic; much of Newton, especially the southern and western parts, are predominantly Jewish). Residents are also, generally, more conservative than those in other parts of 'liberal' Newton.
The Lake gets its name from a now dredged Silver Lake and a popular ballroom which had the same name. Most residents are Italian-American and, to a lesser degree, Irish-American, though "yuppies" are starting to move in for its relatively (for Newton) inexpensive home prices.
Known for a type of slang called "Lake Speak," spoken by some older residents. Please refer to the "Boston Globe" archives for more information. Last, but not least, one of the few sections of Newton where genuine Boston accents ('dropped R's, words such as cahn't, bahthroom, etc.) can be commonly heard.
One will see many bumper stickers, usually on Buicks, Chryslers, Dodges, and Mercurys (and usually driven by older people) commemorating "The Lake (ballroom)," with the colors of the Italian Flag on it.
People who think of Newton as an affluent, predominantly Jewish city where most adults hold graduate degrees are surprised to hear of a neighborhood (The Lake) that has more in common, socio-economically, with Malden or Quincy than with areas of Newton south of the Mass Pike.