Need a chatbot configured to auto-detect visitor language

I run a small online business with visitors from several countries, and right now my chat widget only replies in one language no matter who writes in. I need someone to configure the bot so it automatically figures out which language to use — either by reading the visitor's browser locale the moment the widget loads, or by analyzing the very first message they type — and then answers in that language from the first line, without defaulting to English for everyone.

I also want a simple manual override: a small switcher the visitor can click once to change the reply language mid-conversation, in case the automatic guess is wrong. All canned responses, greetings, and quick-reply buttons should live in one shared answer base with parallel versions per language, so I'm not maintaining separate bots that drift out of sync over time.

Please test the setup with different browser locales and with messages in each supported language, confirm sensible fallback behavior when detection fails, and leave short notes on adding a new language later.

Scope of work:
— automatic language detection from browser settings and first-message analysis
— one-click manual language switcher inside the chat widget
— one multilingual response base instead of separate bots
— tested fallback logic for undetected languages