| 2-step | 1991 | ↓⊕United States | ||
| ABC | 1991 | ↓⊕Sound-Performance | ↓⊕United Kingdom | |
| ACIS | 1991 | |||
| AIMMS | 1991 | |||
| AKL | 1991 | ↓⊕Japan | Andorra Kernel Language | |
| AL | 1991 | ↓⊕United States | TSL knowledge representation language | |
| ALJABR | 1991 | ↓⊕United States | MACSYMA for the Mac | |
| ALMS | 1991 | parallel langauge | ||
| ANALITIK-91 | 1991 | ↓⊕United States | ||
| Andorra-I | 1991 | ↓⊕United Kingdom | Bristol U Andorra | |
| ASCEND | 1991 | |||
| Bob | 1991 | Tiny object-oriented language | ||
| C flat | 1991 | ↓⊕United States | obscurantist C | |
| C+@ | 1991 | ↓⊕United States | Simplified C | |
| C++Linda | 1991 | ↓⊕Germany | ||
| Calico | 1991 | ↓⊕United States | ||
| cantata | 1991 | ↓⊕United States | ||
| CECIL | 1991 | ↓⊕Prototyping | ↓⊕United States | Prototyped OOL |
| Closette | 1991 | ↓⊕United States | ||
| ConC | 1991 | |||
| coq | 1991 | ↓⊕France | ||
| CPL | 1991 | ↓⊕United Kingdom | Categorical Programming Lanugage | |
| CUP | 1991 | ↓⊕Japan | ||
| DataVis | 1991 | ↓⊕United States | ||
| DDL | 1991 | ↓⊕United States | Data Definition Language | |
| Dee | 1991 | ↓⊕Canada | ||
| DEL | 1991 | ↓⊕Brazil | Data Entry Language | |
| Delirium | 1991 | ↓⊕United States | ||
| DESMO | 1991 | ↓⊕Germany | ||
| DICE | 1991 | ↓⊕United States | OO CAE system | |
| DICON | 1991 | ↓⊕United States | ||
| DOHJI | 1991 | ↓⊕Japan | ||
| DTL | 1991 | ↓⊕Netherlands | ||
| Duration Calculus | 1991 | ↓⊕United Kingdom | ||
| dVoice | 1991 | ↓⊕Labelled Matrix | ↓⊕United States | Voice-capable dBase |
| DYNO | 1991 | ↓⊕United States | ||
| EDX/EDL | 1991 | |||
| Eiffel 3 | 1991 | ↓⊕France | ||
| Eiffel/S | 1991 | ↓⊕Germany | SIG Eiffel | |
| ELSIE | 1991 | ↓⊕United Kingdom | ||
| EPL | 1991 | ↓⊕Algebraic | ↓⊕United States | Equational language for parallel scientific applications |
| EPOCH | 1991 | ↓⊕Japan | ||
| ERAE | 1991 | |||
| Erasmus | 1991 | |||
| ESL | 1991 | ↓⊕Robotics | ↓⊕United States | |
| expect | 1991 | ↓⊕United States | ||
| Express | 1991 | ↓⊕United States | NIST Data definition language | |
| Fibonacci | 1991 | ↓⊕International | ||
| FLEX | 1991 | ↓⊕United States | Dynamic real-time language | |
| FORKADS | 1991 | ↓⊕United States | ||
| FORMAN | 1991 | ↓⊕United States | ||
| Formula | 1991 | ↓⊕United States | ||
| Fortran D | 1991 | ↓⊕United States | Parallel extension to FORTAN | |
| Fortran-Linda | 1991 | ↓⊕Ireland | ||
| FX-91 | 1991 | ↓⊕United States | ||
| GAML | 1991 | Parallel Lazy ML | ||
| GCLA | 1991 | ↓⊕Sweden | ||
| Glue-Nail | 1991 | ↓⊕United States | ||
| Gofer | 1991 | ↓⊕United Kingdom | ||
| GRAP | 1991 | ↓⊕United States | ||
| Grapes | 1991 | |||
| Haskell# | 1991 | ↓⊕United States | Parallel dialect of Haskell | |
| Hence | 1991 | Visual languages | ||
| hepawk | 1991 | ↓⊕Germany | ||
| HPCode-Plus | 1991 | ↓⊕United States | ||
| HSL | 1991 | ↓⊕United States | ||
| HyTime | 1991 | ↓⊕United States | ||
| iGlue | 1991 | ↓⊕United States | ||
| IRDATA | 1991 | ↓⊕Germany | ||
| Iris | 1991 | ↓⊕United States | ||
| Isabelle-91 | 1991 | ↓⊕United States | ||
| ISL | 1991 | ↓⊕United States | Interface Specification Language | |
| ITL | 1991 | ↓⊕Italy | ||
| Jade | 1991 | ↓⊕United States | Device independant parallel programming language | |
| jBasic | 1991 | ↓⊕United States | ||
| JOSIE | 1991 | ↓⊕Frame languages | ↓⊕United States | |
| Kaleidoscope'91 | 1991 | ↓⊕United States | ||
| Kid | 1991 | ↓⊕United States | ||
| King Kong | 1991 | ↓⊕Frame languages | ↓⊕United States | |
| KMODEL | 1991 | ↓⊕Germany | ||
| KRIS | 1991 | ↓⊕United States | ||
| LCL | 1991 | |||
| LIANA | 1991 | ↓⊕United States | Interpretive c-like language | |
| Lingo | 1991 | ↓⊕Animation | ↓⊕United States | Macromedia animation scripting language |
| LinxBasic | 1991 | ↓⊕Street basics | ↓⊕Canada | Generator language |
| log | 1991 | ↓⊕United States | ||
| LOLA | 1991 | ↓⊕Germany | ||
| LPMud | 1991 | ↓⊕Sweden | ||
| Lucid representations | 1991 | ↓⊕United States | ||
| Lucinda | 1991 | ↓⊕United Kingdom | ||
| MACL | 1991 | ↓⊕United States | Macintosh Allegro CL | |
| MacOberon | 1991 | ↓⊕Switzerland | ||
| Maggiolo-Schettini 3 | 1991 | |||
| MAL | 1991 | Modal action logic | ||
| Maril | 1991 | |||
| mawk | 1991 | |||
| MCL | 1991 | ↓⊕United States | Macintosh Common LISP | |
| Megalog | 1991 | ↓⊕United Kingdom | ||
| Meroon | 1991 | ↓⊕France | ||
| MIDAS | 1991 | ↓⊕United States | Bell Labs Simulator | |
| Miracula | 1991 | ↓⊕United Kingdom | ||
| M-LISP | 1991 | ↓⊕Lazy Evaluation LISPs | ↓⊕United States | |
| Mma | 1991 | ↓⊕Algebraic | ↓⊕United States | Mathematical system |
| Modula SC | 1991 | ↓⊕Switzerland | Modula 2 with Scientific Ccomputing extensions | |
| Morpheus | 1991 | |||
| NESL | 1991 | ↓⊕United States | ||
| Neuro-Prolog | 1991 | ↓⊕Horn clause | ↓⊕Japan | |
| Neuro-Prolog II | 1991 | ↓⊕Horn clause | ↓⊕Japan | |
| nML | 1991 | ↓⊕Grammar and Syntax-oriented | ↓⊕United States | Grammar specification language |
| NSL | 1991 | |||
| NSL | 1991 | ↓⊕United States | ||
| NUA-Prolog | 1991 | ↓⊕Horn clause | ↓⊕United Kingdom | Extension to the WAM for Parallel Andorra |
| NUE-Prolog | 1991 | ↓⊕Horn clause | ↓⊕Australia | |
| Oberon-2 | 1991 | ↓⊕Switzerland | ||
| Object-Oriented Turing | 1991 | ↓⊕Canada | ||
| Object-Z | 1991 | ↓⊕Australia | ||
| Omega | 1991 | ↓⊕Prototyping | ↓⊕Austria | Protype based OOL |
| OOT | 1991 | ↓⊕Canada | ||
| O'Small | 1991 | ↓⊕United States | ||
| Paragon | 1991 | |||
| Parallaxis 2 | 1991 | ↓⊕Germany | ||
| ParaMacs | 1991 | ↓⊕United States | ||
| PARIS | 1991 | ↓⊕Pascals | ↓⊕Russian Federation | Siberian parallel Pascal |
| Parsec | 1991 | ↓⊕United States | C-based parallel simulation language | |
| PARULEL | 1991 | |||
| Pascal-Linda | 1991 | ↓⊕Pascals | ↓⊕United Kingdom | |
| Pascal-XSC | 1991 | ↓⊕Pascals | ↓⊕Germany | |
| pC++ | 1991 | |||
| Persimmon | 1991 | ↓⊕Australia | ||
| PFC | 1991 | ↓⊕United States | ||
| Pi Calculus | 1991 | ↓⊕United Kingdom | ||
| PICL | 1991 | ↓⊕United States | ||
| PICL | 1991 | ↓⊕Italy | ||
| PICT | 1991 | ↓⊕United Kingdom | ||
| PiCTeX | 1991 | ↓⊕2d shape | ↓⊕United States | Picture extensions to TeX |
| Poco | 1991 | ↓⊕United States | ||
| PREDULA | 1991 | ↓⊕Pascals | ↓⊕Sweden | Data-parallel Pascal |
| PROCOL | 1991 | |||
| PROGRES | 1991 | ↓⊕Germany | ||
| PROOF/L | 1991 | |||
| PROSIT | 1991 | ↓⊕United States | Programming in SItuation Theory | |
| pSather | 1991 | ↓⊕United States | parallel Sather | |
| PSDL | 1991 | |||
| Python | 1991 | ↓⊕Netherlands | String based scripting language | |
| QUINE | 1991 | ↓⊕United States | ||
| Quintec Prolog | 1991 | ↓⊕Horn clause | ↓⊕United Kingdom | |
| Quintec-Objects | 1991 | ↓⊕United Kingdom | ||
| Quixote | 1991 | ↓⊕Japan | ||
| RC | 1991 | ↓⊕France | Reactive C | |
| RDL | 1991 | ↓⊕United States | ||
| Real-Time Concurrent C | 1991 | ↓⊕CPL, BCPL and B | ↓⊕United States | Real-time extensions to Concurrent C |
| REDUCE/OR | 1991 | ↓⊕United States | parallel language | |
| R-Prolog | 1991 | ↓⊕Horn clause | ||
| RSML | 1991 | ↓⊕Decision tables | ↓⊕United States | Hardware requirements DT language |
| Sampletalk | 1991 | ↓⊕Russian Federation | ||
| Sather | 1991 | ↓⊕United States | ||
| Sather 0 | 1991 | ↓⊕United States | ISCI version of programming by contract | |
| Self-91 | 1991 | ↓⊕United States | Instance-based OO Language | |
| SetLog | 1991 | ↓⊕United States | ||
| Sim++ | 1991 | |||
| Siri | 1991 | ↓⊕United States | ||
| SNOOPS | 1991 | ↓⊕United States | ||
| Sqil | 1991 | ↓⊕France | Intermediate language for functional programming languages | |
| SQLMP | 1991 | ↓⊕United States | Linear programmign extensions to SQL | |
| STAR | 1991 | ↓⊕Russian Federation | ||
| Starlog | 1991 | ↓⊕Interval time | ↓⊕Canada | Stratified Temporal Prolog |
| STARSET | 1991 | ↓⊕Russian Federation | Distributed databases programming language | |
| STARSIM | 1991 | ↓⊕United States | Simulator for *Lisp | |
| Synon/1 | 1991 | |||
| SYNON/2 | 1991 | |||
| Terse | 1991 | |||
| TIM | 1991 | ↓⊕France | ||
| TL0 | 1991 | ↓⊕United States | ||
| Tortoise | 1991 | |||
| TPDL* | 1991 | |||
| Trafola-H | 1991 | |||
| UBASIC | 1991 | ↓⊕Japan | Symbolic maths BASIC | |
| UDL/I | 1991 | ↓⊕Japan | ||
| UltraCPL | 1991 | ↓⊕Numerical Control | ↓⊕United States | CAM systems language |
| USL | 1991 | ↓⊕United States | ||
| VCODE | 1991 | ↓⊕United States | Intermediate language used in the compilation of C+@ | |
| VCODE | 1991 | ↓⊕United States | Intermediate language used in the compilation of NESL | |
| Venus | 1991 | |||
| VPL | 1991 | |||
| WCL | 1991 | ↓⊕Lazy Evaluation LISPs | ↓⊕United States | CLX optimised for multiple programs |
| WinNodal | 1991 | |||
| WinSTRUDL | 1991 | ↓⊕United States | STRUDL for Windows | |
| Xfun | 1991 | ↓⊕France | ||
| x-kernel | 1991 | |||
| Zipcode | 1991 | Parallel language at Lawrence Livermore | ||
| Zuse | 1991 | ↓⊕Pascals | ↓⊕Sweden |