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

LTR

   Langage Temps-Réel.

   (French for "real-time language") A French predecessor to
   Ada, LTR is Modula-like with a set of special-purpose
   real-time constructs based on an event model.  It was
   mentioned in the reference below.

   ["An Overview of Ada", J.G.P. Barnes, Soft Prac & Exp
   10:851-887 (1980)].

   (1995-01-31)