| 3APL | 1998 | ||||
| ABCL/R3 | 1998 | ↓ ↑ ⊕ Experimental and other | ⊕ Actor | ⊕ Japan | Concurrent object-oriented language |
| Algol 48 | 1998 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True Algol58s | ⊕ United States | McCarthy's putative theorised Algol 50 precursor |
| Algol 50 | 1998 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ United States | McCarthy's putative theorised Algol 60 precursor |
| Alma-O | 1998 | ↓ ↑ ⊕ Experimental and other | ⊕ Netherlands | Hybrid I/D language | |
| AML | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | Anil | |
| APROL | 1998 | ↓ ↑ ⊕ String and List Processing | ⊕ Array | J with a Scheme flavour | |
| ARLO | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | ||
| ATSQL2 | 1998 | ⊕ International | |||
| BaLinda K | 1998 | ↓ ↑ ⊕ String and List Processing | ⊕ Singapore | ||
| BALSA | 1998 | ⊕ United Kingdom | |||
| Bison++ | 1998 | ⊕ United States | |||
| Bramble | 1998 | ⊕ Japan | |||
| C++// | 1998 | ⊕ United States | Concurrent OO Language | ||
| Cactus | 1998 | ⊕ Greece | |||
| Catalysis | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | Object modelling language | |
| Cayenne | 1998 | ⊕ Sweden | |||
| CDL3 | 1998 | ⊕ Netherlands | Version 3Compiler Description Language | ||
| Chicon | 1998 | ⊕ China | |||
| chpp | 1998 | ↓ ↑ ⊕ String and List Processing | ⊕ Austria | Macro compiler | |
| CLeogo | 1998 | ↓ ↑ ⊕ String and List Processing | ⊕ List | ⊕ New Zealand | Collaborative Leogo |
| ColaS | 1998 | ||||
| Cole | 1998 | parallel language | |||
| Concurrent CLU | 1998 | parallel language | |||
| COSY | 1998 | ||||
| cql | 1998 | ||||
| Cyclone | 1998 | ⊕ United States | |||
| Darlington | 1998 | parallel language | |||
| dataparallel C | 1998 | parallel language | |||
| DCL | 1998 | DIGITAL Command Language | |||
| DeLis | 1998 | ||||
| DESMO-C | 1998 | ||||
| Elan | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ France | Constraint logic program | |
| E-LOTOS | 1998 | ⊕ Belgium | |||
| Enterprise | 1998 | parallel language | |||
| Euris | 1998 | ⊕ Netherlands | |||
| FORK | 1998 | ↓ ↑ ⊕ Experimental and other | ⊕ Austria | PRAM-language | |
| FrameWork | 1998 | ⊕ Japan | |||
| FranTK | 1998 | ⊕ United States | |||
| GAEA | 1998 | ⊕ Japan | |||
| GJ | 1998 | ⊕ United States | Generic Java | ||
| Golex | 1998 | ⊕ Robotics | ⊕ Germany | ||
| Green | 1998 | ⊕ Brazil | Reflective oo language | ||
| GReQL | 1998 | ||||
| Guaraná | 1998 | ↓ ↑ ⊕ Multi-purpose | ⊕ OO C family | ⊕ Brazil | refelective Java |
| Half Life | 1998 | ⊕ United States | |||
| hHLDS | 1998 | ⊕ Italy | homogeneous HLDS | ||
| HLDS | 1998 | ⊕ Italy | |||
| HPC++ | 1998 | ⊕ United States | |||
| HSML | 1998 | ⊕ Canada | |||
| IL | 1998 | ⊕ United States | |||
| JML | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | Interface specification language for JAVA | |
| JPF | 1998 | ⊕ United States | |||
| Kaleidoquery | 1998 | ⊕ United Kingdom | |||
| KENZO | 1998 | ⊕ France | |||
| LARD | 1998 | ||||
| Link | 1998 | ||||
| LIRESNE | 1998 | ||||
| LogP | 1998 | parallel language | |||
| LogTalk | 1998 | ↓ ↑ ⊕ Experimental and other | ⊕ Portugal | OO Extensions to Prolog | |
| LPL | 1998 | ⊕ Lebanon | Logic Programming Language | ||
| LPL++ | 1998 | ⊕ Lebanon | |||
| M2001 | 1998 | ⊕ United States | |||
| Mallet | 1998 | ⊕ France | |||
| match and move | 1998 | parallel language | |||
| Movie | 1998 | parallel language | |||
| MPI | 1998 | parallel language | |||
| multiprefix | 1998 | parallel language | |||
| NDL | 1998 | ⊕ Sweden | Narrative Description Language | ||
| NML | 1998 | ⊕ Germany | |||
| Oberon-XSC | 1998 | ⊕ United States | |||
| Object-COBOL | 1998 | ↓ ↑ ⊕ Business Data Processing | ⊕ United States | MicroFocus OO Cobol | |
| Opera | 1998 | parallel language | |||
| OPL | 1998 | ⊕ United States | |||
| Opus | 1998 | ⊕ Austria | Multidisciplinary Applications Language | ||
| OX | 1998 | Matrix programming language | |||
| P3L | 1998 | ||||
| Palm | 1998 | parallel language | |||
| Paralf | 1998 | parallel language | |||
| parallel sets | 1998 | parallel language | |||
| PCL | 1998 | Modelling language | |||
| PICO | 1998 | ⊕ Belgium | |||
| picoPERC | 1998 | ||||
| PLAN | 1998 | network programminglanguage | |||
| PQL | 1998 | ||||
| PRAM | 1998 | parallel language | |||
| PROMELA ++ | 1998 | ⊕ United States | |||
| Protium | 1998 | ⊕ Australia | Polymorphic language | ||
| QML | 1998 | ||||
| RAO | 1998 | ||||
| rdfDB | 1998 | ||||
| RLaB | 1998 | ||||
| RobotScript | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ Robotics | ⊕ United States | Scripting language for robots |
| RPC | 1998 | parallel language | |||
| RSF | 1998 | ⊕ Canada | |||
| SA-C | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ United States | Parallel C | |
| SDL | 1998 | Parallel OO language | |||
| SEQUENCE L | 1998 | ||||
| SI Library | 1998 | ||||
| SIL | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ Germany | Stack Intermediate Language | |
| SiLRI | 1998 | ||||
| SIMPL+ | 1998 | ⊕ United States | |||
| SmallScript | 1998 | ⊕ United States | |||
| SOFA | 1998 | ⊕ Germany | |||
| SPLAW | 1998 | ⊕ China | |||
| STATEMATE | 1998 | ⊕ 2D Statecharts | ⊕ Israel | ||
| SYMPAL | 1998 | ||||
| Synchronizers | 1998 | ||||
| TAL | 1998 | ↓ ↑ ⊕ Experimental and other | ⊕ Sweden | Temporal Action Logics | |
| TAL/T | 1998 | ⊕ United States | |||
| TDL | 1998 | ↓ ↑ ⊕ Specialised Languages | ⊕ Robotics | ⊕ United States | |
| TINT | 1998 | ⊕ United States | Trac variant | ||
| Titanium | 1998 | ↓ ↑ ⊕ Numerical Scientific | ⊕ United States | Parallel dialect of Java | |
| TOOLBUS | 1998 | ||||
| TyRuBa | 1998 | ⊕ Belgium | |||
| Vector PASCAL | 1998 | ↓ ↑ ⊕ Multi-purpose | ⊕ Pascals | ⊕ United Kingdom | |
| XML | 1998 | ⊕ International | |||
| XSLT | 1998 | ⊕ International |