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

TPL

   1. Table Producing Language.  "The Bureau of Labor Statistics
   Table Producing Language (TPL)", R.C. Mendelssohn, Proc ACM
   Annual Conf (1974).

   2. Fleming Nielson.  A concurrent functional language.

   3. Terminal Programming Language.  Texas Inst, late 70's.
   Used on the TI-990/1 Small Business Computer and the TI-771
   Intelligent Terminal.