Catcher in the Rye- Narration

The Catcher in the Rye
by J.D. Salinger
pgs 53-105

One thing I'm very curious about, is who Holden is actually talking to.  The narration is first person, and he's narrating his current life events like he's telling a friend a story.  Sometimes it sounds like Holden is just talking or thinking out loud to himself.  But then, there are other cues that suggests he is addressing an outside person.  He explains and describes things in detail like the listener is not aware of common knowledge such as Holden's school and family.  But the diction and narration are very informal and comfortable.  Holden uses a lot of slang and cuss words.  When talking about his kid sister Phoebe, he says, "You'd like her" (Salinger, 67).  "I don't want you to get the idea she was an icicle or something..." (Salinger, 79).  These quotes suggest that Holden knows the listener well enough to know how said person would think.
The listener or the audience of the story may never be totally spelled out, but the informal diction and narration add a different dimension to the story.  Even though the narration is first person, things are revealed to the reader that Holden himself doesn't explicitly state.  His actions, words, and the actions of others all help reveal his character and personal feelings and beliefs.