Respuesta :
Answer: his first language is not English
Explanation: based on the passage, the father, doesn't speak English nor does he knows all the grammatical rules in English.
If he only speaks English to his daughter, or speaks English as well as she does, this still Indicate that English is still not his first language.
So he wouldn't be at fault, if he speaks English only to his daughter, or speaks English as much as his daughter does, Or saying he doesn't know the grammatical rules in English language.
Conclusion about the father is that, is not his first language.