According to Dave Rich
Superlog was originally designed to be a complete remake of Verilog using more modern programming concepts. My role as the company’s first application engineer was simply to convince people to use it. However, after working at four different Verilog start-ups, I realized how important it was to support legacy code and that migration to a new language must come in the form of evolution, not revolution. So we changed the design of Superlog to be 100% backward compatible with Verilog, as SystemVerilog is today.