General lack of clarity about input/output/context languages

[domenic]

If you try to summarize Japanese text, should you expect a Japanese summary? Or an English summary?

What if you provide your { context } or { sharedContext } in a third or fourth language?

How do the answers to these questions interact with summarizerCapabilities.languageAvailable()? Currently it's only intended to give an answer for input language support.

Should we allow web developers to specify the output language more tightly? If so, how could we guarantee the result---would we pass it through translation APIs behind the scenes? Or just fail if it's not supported, and let developers do the translation themselves?