Somebody who does not speak your language still has money to spend and a problem to solve. Right now that call ends in an apology and a hang-up.
Detected in the opening seconds. The caller does not choose from a menu.
The whole conversation, not a translated fragment.
Summary and appointment arrive in your language.
Conversation. It speaks the language rather than translating a script into it.
It follows. People who are more comfortable in a second language often switch halfway.