Autocorrecting of " to « in macOS TextEdit, Notes, etc

When I type " , it is replaced with « throughout macOS.

This has only just started so I have clearly inadvertently changed a setting.

Looks to me as if it thinks I am working with French rather than English.

But I have hunted high and low in MacOS keyboard and language settings but can't find the setting I need.

Does anyone have any ideas please?

Thank you!