Is the AI's English really business-grade?

It's standard professional English: short sentences, one question at a time, polite register by default — not approximate regional English. It handles everyday business vocabulary: quotes and estimates, availability, address, confirmation, follow-up. Honest limit: it won't play with very local idioms — for a nuance-sensitive client, the full transcript lets you take over at the right moment. The English tone of your line is set separately from French, more formal if your clientele requires it.