Simple Grammar?

[Ms. James]

My nine year old daughter apparently answered a question wrong on a test. It's not a big deal, but it just didn't look right to me. The directions were to rewrite each sentence, using the correct form of the adjective in parentheses. The sentence was:
Mother is (unhappy) than Father about the crowding.
My daughter rewrote the sentence to be:
Mother is more unhappy than Father about the crowding.
Her teacher corrected it with:
Mother is unhappier than Father about the crowding.
Which is correct? I thought "more unhappy" looked and sounded correct, am I crazy?

[Tdol]

Generally, two-syllable adjective ending -y form the comparative by changing to -ier, and this can extend to forms, like 'unhappier', with a negative prefix. However, I think it's stretching a point a bit to say that 'more unhappy' is an error. I would say that both are fine, because three-syllable adjectives generally take more/most.
There is an argument between people who look at grammar as a way of transmitting rules and those who look at the way speaker actually use the language, and I think you daughter's teacher falls into the first group.

If we look at actual usage, then I think your daughter's case is fine:

Results from Google
"more unhappy"- 228,000
"unhappier"- 134,000

"happier"- 38,400,000
"more happy"- 1,800,000

I think these figures suggest that your daughter's answer was fine.