| DEL | ⊕ 1971 | ↓ ↑ ⊕ Experimental and other | ⊕ Intermediate languages and VMs | ⊕ United States | Variable instruction set abstract interpreter |
| ISPL | ⊕ 1971 | ↓ ↑ ⊕ Experimental and other | ⊕ United States | Incremental System Programming Language | |
| MPL | ⊕ 1971 | ↓ ↑ ⊕ Experimental and other | ⊕ Microprogramming and HLAs | ⊕ United States | MicroProgramming Language |
| PEESPOL | ⊕ 1971 | ↓ ↑ ⊕ Experimental and other | ⊕ Microprogramming and HLAs | ⊕ United States | UoI microprogramming system |