You can speak one language, switch to another language for one word, and continue speaking in the previous language.
But that's my point. You'll stop, switch, speak, stop, switch, resume. You're not going to be "I was in 東京 yesterday" as a single continuous sentence. It'll have to be broken up to three separate sentences spoken back to back, even for humans.
But that's my point. You'll stop, switch, speak, stop, switch, resume. You're not going to be "I was in 東京 yesterday" as a single continuous sentence. It'll have to be broken up to three separate sentences spoken back to back, even for humans.