Syntax
Input (using the WRITE IN instruction) and output (using the READ OUT instruction) do not use the usual formats; in INTERCAL-72, WRITE IN inputs a number written out as digits in English (such as SIX FIVE FIVE THREE FIVE), and READ OUT outputs it in 'butchered' Roman numerals. More recent versions have their own I/O systems.
Comments can be achieved by using the inverted statement identifiers involving NOT or N'T; these cause lines to be initially ABSTAINed so that they have no effect. (A line can be ABSTAINed from even if it doesn't have valid syntax; syntax errors happen at runtime, and only then when the line is un-ABSTAINed.)
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