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]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "lingo":
   argot, cant, dialect, gibberish, gobbledygook, idiom, jargon,
   language, langue, lingua, locution, mumbo jumbo, mumbo-jumbo,
   parlance, parole, patois, patter, personal usage, phraseology,
   pidgin, scatology, slang, speech, taboo language, talk, tongue,
   usage, vernacular, vocabulary, vulgar language



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

Lingo

   An animation scripting language.

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