What Chui transcribes and summarises in, and what the application itself speaks.
Chui works in the language the meeting was actually held in. The transcript comes back in it and so does the summary — Bulgarian, English, German, Spanish, French, Italian, Portuguese, Dutch, Polish, Czech, Slovak, Hungarian, Romanian, Greek, Croatian, Bosnian, Serbian, Macedonian, Russian or Turkish, and a meeting held in another language the transcription recognises gets its summary in that language too. Serbian, Macedonian and Russian meetings are told apart from Bulgarian by their own letters, so each is summarised in its own language. An English word in the middle of a French sentence is expected, not treated as a mistake, so a meeting full of «deploy», «sprint» and «churn» comes back with those words in it.
What follows from it, in practice:
The application's own interface — every screen, notification and email, and the Lock Screen card — is available in Bulgarian, English, German, Spanish, French, Italian, Hungarian, Polish, Romanian, Greek, Czech, Slovak, Croatian, Bosnian, Macedonian, Serbian (in Cyrillic and in Latin letters), Dutch, Russian, Turkish, and Portuguese as written in Portugal and in Brazil. A phone or browser set to any of them opens Chui in it, and so does the Apple Watch. chui.io answers in the language the reader's browser asks for, except the privacy policy, the terms and the form for reporting illegal content (with its acknowledgement email), which are in English and Bulgarian. A meeting held in a language outside these is still transcribed in its own language and summarised in it; only the buttons around it are in one of Chui's own.
Chui is not built for one language. Its first meetings were held in Bulgarian, which is where the care about switching languages mid-sentence comes from, and none of the languages above — English included — is a second-class setting.
The product is called чуй in Bulgarian — the imperative of "to hear" — and Chui everywhere else. They are the same thing.