"The Smith family live in Canada." and "The Smith family lives in Canada." Which sentence is right?

Question

Answer

The Smith family lives in Canada.
'Family' is the subject, which is singular.

The Smiths live in Canada.
'Smiths' is plural.

Answer

In American English, the word "family" is usually singular: "The Smith family liveS in Canada."

I hear that in some varieties of English, "family" may be plural: "The Smith family live in Canada."

In American English, "family" is only plural if you are thinking about the different members of the family.  Compare:

The Smith family has the biggest house on the block.
The Smith family argue a lot among themselves.