In the English sentence
I asked him
I is the subject, asked is the verb, and him is the direct object.
But in the Spanish translation of the same
Le pregunté
Le, an indirect object pronoun, is used. Why is le used, and not lo?
In the English sentence
I asked him
I is the subject, asked is the verb, and him is the direct object.
But in the Spanish translation of the same
Le pregunté
Le, an indirect object pronoun, is used. Why is le used, and not lo?
Well, I'm not sure about the analysis that you made about the English structure of the sentence.
According to the Cambridge Dictionary
to put a question to someone, or to request an answer from someone:
[ + two objects ] She asked me a question.
What does the highlighted text mean?
[+ two objects] A verb that has a direct and indirect object.
This English Practice site marks the person being asked as the indirect object of the sentence and the question asked as the direct object.
Ask is one of the commonest verbs in English. It is sometimes used incorrectly. The verb ask cannot be followed by the preposition to. It can be followed by either a direct or an indirect object.
Ask John. (Here ask is followed by the indirect object John.)
I want to ask a question. (Here ask is followed by the direct object ‘a question’.)
Note that the indirect object usually refers to a person and the direct object usually refers to a thing.
In Spanish the same occurs: le (a él = him) is the indirect object. Whatever he was asked is the direct object. In your case that element is not explicitly mentioned in the phrase.
After reading the answer provided by David Illescas (+1), I have come with a sort of rule of thumb. In Spanish, as well as in English, we have got a group of verbs to express that a person transmits a piece of information to another person: decir [say], contar [tell], informar [communicate], preguntar [ask], ... etc. In Spanish in all these cases, the piece of information transmitted - the message, the question, the notification, ... - is always the direct object. It may or may not be explicitly present in the sentence. The person that receives the information is always the indirect object.
But, as pointed by David, you may found that the indirect object is represented by the word la when the receiver is a female. This phenomenon is known as "laismo" and its use is extended inside (I'm thinking in Madrid) and outside Spain. You can't parse the sentence just by the way the words "look", you have to know also what they represent, what they mean.
message = direct object
receiver = indirect object
Le is a 3rd person atonic personal pronoun (easy ref)
So, there are some rules if you want to use them (it will be easier to understand if you study DC and IC).
I will explain it in detail:
Full sentence: Él lleva { un regalo } { a Pedro }
The direct complement (DC) is the person, animal or thing on which the action of the verb falls.
DC = un regalo
The indirect complement is the person, animal or thing that indirectly receives the benefit or damage of the action.
IC = a pedro
So, answering your question. According to the RAE:
When the pronoun plays the role of the direct complement, 'lo - los' the masculine (singular and plural, respectively) and 'la - las' the feminine forms (singular and plural, respectively) should be used:
¿Él llevó un regalo a la abuela? Sí, lo llevó.
¿Él ayudó a las niñas? Sí, las ayudó.
When the pronoun performs the function of the indirect complement, the 'le - les' forms (singular and plural, respectively) should be used, regardless of the gender of the word to which the pronoun refers:
Le llevé un regalo a la abuela.
Le pregunté porqué hizo algo tan malvado.
If you have more doubts, you can read about leísmo, laísmo and loísmo (difficult refs)
Question: I asked him I is the subject, asked is the verb, and him is the direct object. But in the Spanish translation of the same Le pregunté Le, an indirect object pronoun, is used. Why is le used, and not lo?
Answer: because lo is a direct object pronoun in Spanish.
You say in Spanish: preguntar algo a alguien, the a alguien signals an indirect object.
the indirect object pronouns in Spanish are:
Me [me] Te [you] Le [her, him, it and you (polite with usted)] Nos [us] Os [plural you in Spanish, in Spain, regular, not polite specifically, just plural: Os pregunté, I asked you [a group of people].] Les [them or you plural, specifically polite when used with Ustedes in Spain. Les pregunté [a ustedes, polite] or Les pregunté [a ellos or a ellas], I asked them.]
That said, beyond the sentence given by the OP, this can become complicated as the usages are not the same in the two languages. It so happens that in the example provided, they are.
Actually, "him" is an indirect object also in the English sentence. To clarify this, let's look at a sentence with two objects:
I asked him a question.
"Question" is the direct object an "him" is the indirect object. Now, consider:
"Sorry, who were you asking -- him or me?"
"I asked him. I know you know the answer. Thanks for checking."
"Him" is still an indirect object, and the direct object doesn't appear -- it's implied, but not explicitly stated.
Sorting out which objects in English are direct or indirect sometimes takes a bit of thought, because they look the same.