Computer languages are used in different contexts, such as software development, release engineering, and performance engineering, and on different platforms like operation systems and integrated development environments (IDEs). These use cases and platforms have different characteristics and impose requirements on a language and its tooling. Developing a language and tooling that works in many contexts and platforms is hard, time consuming, and is not something that language engineers should be spending time on. Language workbenches alleviate a large part of this problem by providing IDE and command-line runtimes which run languages created with that language workbench. However, each language workbench has their own runtime system, resulting in a lot of duplicated effort and no easy way to interoperate between languages developed with different workbenches. A common core for language tools can serve as a library for language workbench runtime systems to prevent duplicated effort and support interoperability. We have inspected existing language workbenches and have ideas for a common architecture, but we have most likely not thought of everything. We think it will be an interesting topic for a discussion in the area of language tools.