The document discusses intermediate language design for virtual machines to provide comprehensive concurrency support. It surveys 17 existing virtual machines to evaluate their concurrency support and models. Only 6 provided explicit concurrency support in the intermediate language. Support ranged from low-level instructions to high-level constructs in standard libraries. To enable new concurrency concepts, future virtual machines need intermediate languages that support both low-level and high-level concurrency features, with an open question around the tradeoffs of features in the intermediate language versus the standard library.