You might also want to consult Twain's *Autobiogaphy* ( the 1924 Paine
edition, *not* the 1959 Neider abridgement), which has several sections
on Twain's ideas about speaking technique.  You should be able to find the
relevant sections by skimming the index; if memory serves, Twain makes
some interesting comments about his oral technique in the section about
the story "His Grandfather's Old Ram," which first appeared as chapt. 53
of *Roughing It* (although come to think of it, this discussion may appear
only in the Neider edition--charting the textual chaos of Twain's auto-
biography is an exasperating task, is it not?).
  My own notion on the topic is that Twain's ideas about orality are
largely in evidence in his fiction.  That is, it seems to me that Twain
(on the stage or the page) rarely hides the *machinery* of his comedy:
the audience is supposed to know they're being fooled, not be surprised by
a punch line.  His humour, in other words, resides more in style, delivery,
and timing than it does in a sudden change in content.  In a Twain story,
as in a Twain routine, the punch line is always evident, even repeated,
whether that punch line is "Well, I don't see no p'ints about that frog
that's any better'n any other frog" ("The Celebrated Jumpin Frog") or "I'm
speaking from the grave" (*Autobiography*).  Twain's well-known disgust
for practical jokes and jokers stems not, as Van Wyck Brooks was perhaps
the first to suggest, from a distaste for violence, but rather from the
fact that in a practical joke, the machinery is always concealed until
the joke is sprung.

Nick Mount
Dalhousie U