My family is eating dinner in the restaurant.

[Alice Chu]

Please tell me if my understanding is correct.
1) My family is eating dinner in the restaurant.
→ In American English, collective noun “family” referring to different members is used with a singular verb.

2) My family are having dinner at the restaurant.
→ In British English, collective noun “family” referring to different members is used with a plural verb.

3) My family is a small one.
→ Both British and American English use a singular verb here. When a collective noun refers to a whole, it is singular.

 

[emsr2d2]

I'd use "is" in #2, in BrE.

 

[jutfrank]

I don't agree with your understanding, Alice.

I don't think there's much (if any) significant difference between varieties of English. It's much more about meaning. If we're thinking about a singularity, we use a singular agreement. I believe it's basically as simple as that.

 

[GoesStation]

Americans rarely treat "family" as a plural, though it's far from unknown. Treating mass nouns as plurals is one of the markers of British English to American ears.

 

[Yankee]

I'd use "is" in #2, in BrE.

Me too in AmE.