Saying something doesn't mean you know how to spell it so the sentence does make sense. If it had been "Cómo se dice gato en español" then it would not make sense.
There still wouldn't be any use for the "en español." An English speaker isn't likely ask "How do you spell cat in English?"; they're more likely to say something like "How do you spell the word cat?"
Correct me if I'm wrong, but it's my impression that Spanish speakers use the verb "escribir" to express the idea of the English verb "spell." In other words, an alternative (and probably better) way to translate this sentence would be "How do you spell 'cat'?"
That's most likely true. In Polish, we commonly say literally "how do you write [word]?" when we really mean to ask for spelling. Wouldn't native English speaker understand it the same way?
In the Collins online Spanish-English dictionary, at Collinsdictionary.com, the second meaning of escribir, after "to write", is
to spell, an example
“voy” se escribe con “v”
“voy” is spelled with a “v”
Linguee though lists to spell as one of the less used meanings.
For those who believe the Duo sentence is nonsensical, if this question is heard and not read it makes complete sense. After all, we are learning to speak and listen as well as to write Spanish, as mikeylee48 points out. I view the written words as being an adjunct for learning to converse, so whenever a Spanish sentence requires translation I do my best to listen first and not peek at the written words, so I can hone my listening skills. So this question would not be at all strange in context - say, if a Spanish tutor (orally) asked this question of a learner.
It would be good too if Duo had the option of hiding the written Spanish words so we could choose to disclose them only after listening first.
Great comments! I always thought the verb was deletrear, but I just learned that it is only used when spelling a word out loud---not written. Learn something new every day!
Is this escribe instead of escribes because we are assuming usted rather than tú?
In the passive voice ("is written", in this example) the verb is always conjugated to match the subject---gato escribe. "How is cat written in Spanish?" is a much more accurate translation than "How do you write..."
So "How is dog said in Spanish?" would be ¿Cómo se dice dog en español?
Dugggg is correct. This particular Spanish wording is actually an impersonal construction, so there is no agent named who performs (or does) the action of the verb. So there is no Tú, no Usted, no Ustedes, etc, who is asked to do the writing - in the Spanish wording.
I believe DLs interpretation into English "How do you write cat in Spanish?" simply reflects a colloquial or common English way of asking such a question. You is really meant generally, so it is a question to anyone. But note that this Spanish construction completely omits naming any agent, and Dugggg's translation is the better literal equivalent of the Spanish wording.
The sentence literally says how to write "cat" is in Spanish. That person is speaking Spanish already after all.
Pretty strange sentence.
??? "Jack" has lots of meanings too in English, but I'm not sure of the relevance here?