Google announced yesterday that the Google Assistant and Google Home can handle questions where you mix your responses between English and another language. Google can handle you asking a question in one language and then following up with another question in a different language.
This is not uncommon for bilingual or multilingual homes where the family will have conversations switching between one language and another. In fact, it is super common for families that grow up speaking another language outside of English in America to do this in the home.
Here is a video of it in action:
The Google AI blog goes into more of how technically it all works.