Jack: Wendy, darling, light of my life, I'm not gonna hurt ya. You didn't let me finish my sentence. I said, I'm not gonna hurt ya, I'm just gonna bash your brains in. Gonna bash 'em right the f*ck in!
Jack Torrance: Wendy, let me explain something to you. Whenever you come in here and interrupt me, you're breaking my concentration. You're distracting me. And it will then take me time to get back to where I was. You understand?
Wendy Torrance: Yeah.
Jack Torrance: Now, we're going to make a new rule. When you come in here and you hear me typing [types], or whether you DON'T hear me typing, or whatever the FUCK you hear me doing, when I'm in here, it means that I am working. THAT means don't come in. Now, do you think you can handle that?
Wendy Torrance: Yeah.
Jack Torrance: Good. Now why don't you start right now and get the fuck out of here?
Wendy Torrance: Stay away from me.
Jack Torrance: Why?
Wendy Torrance: I just wanna go back to my room.
Jack Torrance: Why?
Wendy Torrance: Well, I'm very confused and I just need time to think things over.
Jack Torrance: You've had your whole fucking life to think things over.
What good's a few minutes more gonna do you now?
Jack Torrance: Are you out of your fucking mind?
Grady Twins: Come play with us Danny. For ever and ever and ever.
Jack Torrance: Heeere's Johnny!
Lloyd: Women. Can't live with them, can't live without them.
Jack Torrance: Words of wisdom, Lloyd, my man. Words of wisdom.
Jack Torrance: God, I'd give anything for a drink. I'd give my god-damned soul for just a glass of beer.
Lloyd: What will you be drinking, sir?
Jack Torrance: Hair of the dog that bit me, Lloyd.
Dick Halloran: They turned out to be completely unreliable assholes.
Danny Torrance: Redrum. Redrum. Redrum.
Jack Torrance: Little pigs. Little pigs. Let me come in. Now by the hair on your chinny chinny chin? Then, I'll huff, and I'll puff, and I'll blow your house in!
Jack Torrance: Here's Johnny!
Jack Torrance: Here's to five miserable months on the wagon, and all the irreparable harm it has caused me.
Answer: Delbert Grady has always been at the hotel, just as Jack Torrance has...however, "Charles Grady" was one incarnation of the hotel's "caretaker", which Jack Torrance currently is. Delbert, evidenced by his appearance, occupation, and archaic racial views, has been with the hotel since its turn-of-the-century inception, just as Jack, in the photo at the end, has been. We don't know what "spirit-Jack's" function in the Overlook is...we only know that the present Jack (whom Delbert is talking to) embodies the "caretaker" who has always been there, just as Charles Grady did in his time. Delbert refers to his wife and two daughters, whom he did not murder...his "caretaker" version, Charles Grady, did that.