How would you say, "How long have you been a X?"

Question

I want to say in Latin, "How long have you been a dog? I have been a dog four or five years now."

But how do I form the interrogative phrase, "How long?" My first inclination was to use the phrase "quantus tempus", somehow, but I'm pretty sure this is wrong.

How would you translate my first two examples into Latin? It would be interesting to learn more about how to ask a question regarding time or duration. I know that Greek uses the accusative, dative, and genitive cases to express different aspects of time. Does Latin have an accusative of duration? This would be necessary for translating my second example (i.e. four or five years now).

Answer 1

'For how long' can be rendered quamdiu (or quam diu). In this case, because an ongoing state is described, I'd use a present tense verb. For the answer, the accusative of duration does indeed exist in Latin and will work just fine here:

quam diu canis es? quartum quintumve* iam annum canis sum.

* According to Gildersleeve and Lodge (§336), 'In giving definite numbers with iam, iam diu, iam dudum, etc., the Latin often employs the ordinal where the English prefers the cardinal.'

Answer 2

I suggest that you take a look at this old question about similar structures. The conclusion was that present tense is the way to go.

Latin has an adverb diu, meaning roughly "for a long time". I would ask "how long?" as quam diu? instead of using the word tempus. If you do use tempus, remember that it's a neuter (not quantus tempus). Lengths of time are usually indicated with the accusative and the ablative doesn't fit your dog example, so one option would be the accusative quantum tempus. But quam diu sounds far more idiomatic to me.

Thus, I'd suggest:

"How long have you been a dog?"
Quam diu canis es?
"I have been a dog four or five years now."
Canis sum iam quattuor aut quinque annos.