How Helpinator handles multilingual documentation?

Helpinator was designed to be used as a single-source and multilingual tool. Every project can store any number of languages, preserving the same table of contents and context ids of topics, but each language has it's own content. You can change languages by language selector on the toolbar.

Why is it important?

It significantly decreases workload on content maintainers becuase there's no need to have separate copies of your project for each language, and keeping project structure in-sync between them.

Are there any context-sensitive help systems that are multilingual?

Yes, MajorMindHelp and LiteHelp are multilingual and allow to switch languages using viewer API or using user interface.