The Jargon File (version 4.4.7, 29 Dec 2003):

INTERCAL
 /in't@r?kal/, n.

    [said by the authors to stand for Compiler Language With No Pronounceable
    Acronym] A computer language designed by Don Woods and James Lyons in 1972.
    INTERCAL is purposely different from all other computer languages in all
    ways but one; it is purely a written language, being totally unspeakable.
    An excerpt from the INTERCAL Reference Manual will make the style of the
    language clear:

        It is a well-known and oft-demonstrated fact that a person whose work
        is incomprehensible is held in high esteem. For example, if one were to
        state that the simplest way to store a value of 65536 in a 32-bit
        INTERCAL variable is:


        DO :1 <- #0$#256

        any sensible programmer would say that that was absurd. Since this is
        indeed the simplest method, the programmer would be made to look
        foolish in front of his boss, who would of course have happened to turn
        up, as bosses are wont to do. The effect would be no less devastating
        for the programmer having been correct.

    INTERCAL has many other peculiar features designed to make it even more
    unspeakable. The Woods-Lyons implementation was actually used by many
    (well, at least several) people at Princeton. The language has been
    recently reimplemented as C-INTERCAL and is consequently enjoying an
    unprecedented level of unpopularity; there is even an alt.lang.intercal
    newsgroup devoted to the study and ... appreciation of the language on
    Usenet.

    Inevitably, INTERCAL has a home page on the Web: http://www.catb.org/~esr/
    intercal/. An extended version, implemented in (what else?) Perl and
    adding object-oriented features, is rumored to exist. See also Befunge.


The Free On-line Dictionary of Computing (30 December 2018):

INTERCAL

    /in't*r-kal/ (Said by the authors to stand
   for "Compiler Language With No Pronounceable Acronym").

   Possibly the most elaborate and long-lived joke in the history
   of programming languages.  It was designed on 1972-05-26 by
   Don Woods and Jim Lyons at Princeton University.

   INTERCAL is purposely different from all other computer
   languages in all ways but one; it is purely a written
   language, being totally unspeakable.  The INTERCAL Reference
   Manual, describing features of horrifying uniqueness, became
   an underground classic.  An excerpt will make the style of the
   language clear:

   It is a well-known and oft-demonstrated fact that a person
   whose work is incomprehensible is held in high esteem.  For
   example, if one were to state that the simplest way to store a
   value of 65536 in a 32-bit INTERCAL variable is:

       DO :1 <- #0$#256

   any sensible programmer would say that that was absurd.  Since
   this is indeed the simplest method, the programmer would be
   made to look foolish in front of his boss, who would of course
   have happened to turn up, as bosses are wont to do.  The
   effect would be no less devastating for the programmer having
   been correct.

   INTERCAL has many other peculiar features designed to make it
   even more unspeakable.  The Woods-Lyons implementation was
   actually used by many (well, at least several) people at
   Princeton.

   Eric S. Raymond  wrote C-INTERCAL in
   1990 as a break from editing "The New Hacker's Dictionary",
   adding to it the first implementation of COME FROM under its
   own name.  The compiler has since been maintained and extended
   by an international community of technomasochists and is
   consequently enjoying an unprecedented level of unpopularity.

   The version 0.9 distribution includes the compiler, extensive
   documentation and a program library.  C-INTERCAL is actually
   an INTERCAL-to-C source translator which then calls the local
   C compiler to generate a binary.  The code is thus quite
   portable.

   Intercal Resource Page
   (http://locke.ccil.org/~esr/intercal/).

   Usenet newsgroup: news:alt.lang.intercal.

   ["The INTERCAL Programming Language Reference Manual", Donald
   R. Woods & James M. Lyon].

   [Jargon File]

   (1997-04-09)