Why can you use inversion with nouns in this expression?

Question

According to the lesson 'Forming inverted questions with names, things and emphasis', you can't use inversion with nouns (for example, 'Vient Sophie?'); you need to add a pronoun ('Sophie vient-elle?'). But here in the examples we see 'Comment vont tes enfants?' and 'Comment va Paul?'. Why isn't it 'Comment tes enfants vont?' or 'Comment tes enfants vont-ils?' Is this a peculiarity of this particular expression, or are there other cases where inversion can be used with nouns with no pronoun?

Cécile Janty-Davies · Accepted Answer

Hi D,
To add to what Chris said and to use the example in the lesson 'Sophie vient' the three possible ways to ask if Sophie is coming would be :
Est-ce que Sophie vient?      (using est-ce que)
Sophie vient-elle?        (Inversion)
Sophie vient?   (Intonation rising at the end making it a question)
It is the same with all verbs,
e.g.   Les voitures coûtent cher.
Est-ce que les voitures coûtent cher?
Les voitures coûtent-elles cher?  (Inversion)
Les voitures coûtent cher?
Hope this helps!

Chris Wirt · Answer

Hi D,
"Comment vont tes enfants?" and "Tes enfants comment vont-ils?" are both correct.
The reason you cannot say, e.g., "Vont tes enfants?" is because there is no interrogative pronoun as, e.g., comment, quand, etc.
-- Chris (not a native speaker).