Because "les" is a direct object pronoun. He is writing a book. I.e., "un livre" is the direct object. The "them" means that they are the indirect recipients of the action. We would say "for them". The indirect object pronoun for "them" is "leur", not "les".
- Direct object pronouns : me, te, le/la, nous, vous, les
- Indirect object pronouns : me, te, lui, nous, vous, leur
I answered "He writes a book for them" and it was not accepted. The one given that was supposedly correct was "He writes them a book."
I think Duolingo needs to focus more on communication and meaning than grammar of the 2nd language and word for word translations.
Sure, great grammar is nice, but ACTFL is now creating US curriculum based first and foremost on communications and meaning.
Am I being graded on English grammar here? Perhaps the way I say it is wrong (it is the way we say it where I grew up on the plains in Kansas.
Several people have expressed difficulty with indirect object pronouns. Is it "He writes them a book", "He writes a book FOR them" or "He writes a book TO them"? By far the most common way in British English is to put the indirect object (for or to them) before the direct object. He writes John a book, He writes him a book, He writes them a book is the preferred format. Note that the to or for disappears when the noun or pronoun is in this position. The location of the indirect object directly before the object (book) is enough to show that it is indirect and contains a hidden preposition (to or for). I gave (to) them some food. I read (to) them a book. I wrote (to) them a letter. I wrote (for) them a book. What about to and for? To indicates the recipient of something, "for" more often indicates intention. I give it TO him, I send it TO him (he is the target of my action) but I write it FOR him means he is the reason that I wrote it, he is the intended beneficiary. I wrote a book FOR him indicates that I wrote it so that he could benefit from it, so that I could honour or recognise him in some way, or because I wanted to pay tribute to him in some way. FOR could also indicate that I wrote it on his behalf, because he needed a ghost writer, because he paid me, or that I was somehow the agency through which the book was written in order that he would benefit in some way. TO, on the other hand, simply indicates direction. There is a difference between I wrote a letter to him and I wrote a letter for him. The first indicates that I wrote a letter and sent it to him. The second indicates that I wrote as letter on his behalf, so that he could use it elsewhere to achieve some aim, or because he was unable to write it himself, or because he could derive some other benefit from it. Unfortunately, the English indirect object in He writes THEM a letter or He writes THEM a book does not tell you whether to or for is intended. Context is everything. If we are talking of a book, the meaning must be FOR (beneficiary). If we are talking of a letter, then either TO or FOR would work, but they mean different things.