| 2-step | ⊕ 1991 | ⊕ United States | |||
| AL | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | TSL knowledge representation language | |
| ALJABR | ⊕ 1991 | ⊕ United States | MACSYMA for the Mac | ||
| ANALITIK-91 | ⊕ 1991 | ⊕ United States | |||
| C flat | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | obscurantist C | |
| C+@ | ⊕ 1991 | ↓ ↑ ⊕ Multi-purpose | ⊕ United States | Simplified C | |
| Calico | ⊕ 1991 | ⊕ United States | |||
| cantata | ⊕ 1991 | ⊕ United States | |||
| CECIL | ⊕ 1991 | ↓ ↑ ⊕ Multi-purpose | ⊕ Prototyping | ⊕ United States | Prototyped OOL |
| Closette | ⊕ 1991 | ⊕ United States | |||
| DataVis | ⊕ 1991 | ⊕ United States | |||
| DDL | ⊕ 1991 | ↓ ↑ ⊕ Business Data Processing | ⊕ United States | Data Definition Language | |
| Delirium | ⊕ 1991 | ⊕ United States | |||
| DICE | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | OO CAE system | |
| DICON | ⊕ 1991 | ⊕ United States | |||
| dVoice | ⊕ 1991 | ↓ ↑ ⊕ Business Data Processing | ⊕ Labelled Matrix | ⊕ United States | Voice-capable dBase |
| DYNO | ⊕ 1991 | ⊕ United States | |||
| EPL | ⊕ 1991 | ↓ ↑ ⊕ Numerical Scientific | ⊕ Algebraic | ⊕ United States | Equational language for parallel scientific applications |
| ESL | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Robotics | ⊕ United States | |
| expect | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | ||
| Express | ⊕ 1991 | ↓ ↑ ⊕ Business Data Processing | ⊕ United States | NIST Data definition language | |
| FLEX | ⊕ 1991 | ↓ ↑ ⊕ Multi-purpose | ⊕ United States | Dynamic real-time language | |
| FORKADS | ⊕ 1991 | ⊕ United States | |||
| FORMAN | ⊕ 1991 | ⊕ United States | |||
| Formula | ⊕ 1991 | ⊕ United States | |||
| Fortran D | ⊕ 1991 | ↓ ↑ ⊕ Numerical Scientific | ⊕ United States | Parallel extension to FORTAN | |
| FX-91 | ⊕ 1991 | ⊕ United States | |||
| Glue-Nail | ⊕ 1991 | ⊕ United States | |||
| GRAP | ⊕ 1991 | ↓ ↑ ⊕ Experimental and other | ⊕ United States | ||
| Haskell# | ⊕ 1991 | ↓ ↑ ⊕ Experimental and other | ⊕ United States | Parallel dialect of Haskell | |
| HPCode-Plus | ⊕ 1991 | ⊕ United States | |||
| HSL | ⊕ 1991 | ⊕ United States | |||
| HyTime | ⊕ 1991 | ⊕ United States | |||
| iGlue | ⊕ 1991 | ⊕ United States | |||
| Iris | ⊕ 1991 | ⊕ United States | |||
| Isabelle-91 | ⊕ 1991 | ⊕ United States | |||
| ISL | ⊕ 1991 | ⊕ United States | Interface Specification Language | ||
| Jade | ⊕ 1991 | ⊕ United States | Device independant parallel programming language | ||
| jBasic | ⊕ 1991 | ⊕ United States | |||
| JOSIE | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Frame languages | ⊕ United States | |
| Kaleidoscope'91 | ⊕ 1991 | ⊕ United States | |||
| Kid | ⊕ 1991 | ⊕ United States | |||
| King Kong | ⊕ 1991 | ⊕ Frame languages | ⊕ United States | ||
| KRIS | ⊕ 1991 | ⊕ United States | |||
| LIANA | ⊕ 1991 | ⊕ United States | Interpretive c-like language | ||
| Lingo | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Animation | ⊕ United States | Macromedia animation scripting language |
| log | ⊕ 1991 | ⊕ United States | |||
| Lucid representations | ⊕ 1991 | ⊕ United States | |||
| MACL | ⊕ 1991 | ⊕ United States | Macintosh Allegro CL | ||
| MCL | ⊕ 1991 | ⊕ United States | Macintosh Common LISP | ||
| MIDAS | ⊕ 1991 | ⊕ United States | Bell Labs Simulator | ||
| M-LISP | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Lazy Evaluation LISPs | ⊕ United States | |
| Mma | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Algebraic | ⊕ United States | Mathematical system |
| NESL | ⊕ 1991 | ⊕ United States | |||
| nML | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Grammar and Syntax-oriented | ⊕ United States | Grammar specification language |
| NSL | ⊕ 1991 | ⊕ United States | |||
| O'Small | ⊕ 1991 | ⊕ United States | |||
| ParaMacs | ⊕ 1991 | ⊕ United States | |||
| Parsec | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | C-based parallel simulation language | |
| PFC | ⊕ 1991 | ⊕ United States | |||
| PICL | ⊕ 1991 | ⊕ United States | |||
| PiCTeX | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ 2d shape | ⊕ United States | Picture extensions to TeX |
| Poco | ⊕ 1991 | ⊕ United States | |||
| PROSIT | ⊕ 1991 | ⊕ United States | Programming in SItuation Theory | ||
| pSather | ⊕ 1991 | ↓ ↑ ⊕ Experimental and other | ⊕ United States | parallel Sather | |
| QUINE | ⊕ 1991 | ⊕ United States | |||
| RDL | ⊕ 1991 | ⊕ United States | |||
| Real-Time Concurrent C | ⊕ 1991 | ↓ ↑ ⊕ Experimental and other | ⊕ CPL, BCPL and B | ⊕ United States | Real-time extensions to Concurrent C |
| REDUCE/OR | ⊕ 1991 | ⊕ United States | parallel language | ||
| RSML | ⊕ 1991 | ⊕ Decision tables | ⊕ United States | Hardware requirements DT language | |
| Sather | ⊕ 1991 | ⊕ United States | |||
| Sather 0 | ⊕ 1991 | ⊕ United States | ISCI version of programming by contract | ||
| Self-91 | ⊕ 1991 | ↓ ↑ ⊕ Multi-purpose | ⊕ United States | Instance-based OO Language | |
| SetLog | ⊕ 1991 | ⊕ United States | |||
| Siri | ⊕ 1991 | ⊕ United States | |||
| SNOOPS | ⊕ 1991 | ⊕ United States | |||
| SQLMP | ⊕ 1991 | ⊕ United States | Linear programmign extensions to SQL | ||
| STARSIM | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ United States | Simulator for *Lisp | |
| TL0 | ⊕ 1991 | ⊕ United States | |||
| UltraCPL | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ Numerical Control | ⊕ United States | CAM systems language |
| USL | ⊕ 1991 | ⊕ United States | |||
| VCODE | ⊕ 1991 | ⊕ United States | Intermediate language used in the compilation of NESL | ||
| VCODE | ⊕ 1991 | ⊕ United States | Intermediate language used in the compilation of C+@ | ||
| WCL | ⊕ 1991 | ↓ ↑ ⊕ String and List Processing | ⊕ Lazy Evaluation LISPs | ⊕ United States | CLX optimised for multiple programs |
| WinSTRUDL | ⊕ 1991 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | STRUDL for Windows |