The Collaborative International Dictionary of English v.0.48:

Lingo \Lin"go\ (l[i^][ng]"g[-o]), n. [L. lingua tongue,
   language. See Lingual.]
   Language; speech; dialect. [Slang]
   [1913 Webster]

WordNet (r) 3.0 (2006):

lingo
    n 1: a characteristic language of a particular group (as among
         thieves); "they don't speak our lingo" [syn: slang,
         cant, jargon, lingo, argot, patois, vernacular]

The Free On-line Dictionary of Computing (19 January 2023):

Lingo

   An animation scripting language.

   [MacroMind Director V3.0 Interactivity Manual, MacroMind
   1991].