Biwwy

Biwwy is a child found in Little Lamplight, who resides in the Great Chamber of the settlement. Biwwy has a speech impediment where he pronounces all of his L's and Y's as W's, and if asked why he is named what he is, will respond with "Nickname? What nickname?". He is also unaware of his speech impediment by the fact that when you tell him to stop talking like that he says "Stop tawking wike what? Wou're weiwd."

Biwwy also has a special Laser Rifle, called the Wazer Wifle, that is a bit more powerful than a standard Rifle, and holds a larger magazine. It can be purchased for 500 caps, or gotten freely with the Child at Heart perk. You can also haggle him down to 250 caps if your Barter skill is high enough.

Biwwy lives in the great chamber. Find the blue tarpaulin on the walkway, he lives in an alcove near it.

Bugs
There are also a glitch in which Biwwy is found in the nearby pool of water, so that you cannot talk to him or obtain the Wazer Wifle. If anyone knows how to get around this, please contribute.

Also, if you ask him about getting in the Vault 87, he will not pronounce all of his L's and Y's as W's, despite his speech impediment. This seems to be a speech glitch which Bethesda skipped.