"He writes her a book."
Translation:Il lui écrit un livre.
Why can you not use "la" instead of "lui" and therefore say "Il l'écrit un livre?"
It appears that "la" is a direct object pronoun while "lui" is an indirect object pronoun. In this case, because the verb écrit is not being done to "her", but rather to un livre, "her" is acting as an indirect object pronoun: la.
We have only one pronoun for singular indirect objects to the 3rd person ("lui"), and only one for plural indirect object to the 3rd person ("leur"). That's why we don't use "la" in this exercise.
"Sophie donne une voiture à Marc." "Sophie lui donne une voiture."
"Marc donne une voiture à Sophie." "Marc lui donne une voiture."
Be careful, because "lui" can also be used as a disjunctive pronoun, and in this case, it does have its feminine counterpart, which is "elle".
"Cette voiture est à Marc." "Cette voiture est à lui."
"Cette voiture est à Sophie." "Cette voiture est à elle."
You can find all different personal pronouns on this page:
Perhaps I am not understanding the use of "lui" yet, but isn't the direct translation of "Elle lui écrit un livre" actually "She him/her writes a book", As in, "She writes a book to him/her." All of that is to say, is the subject not always first in French? Thank you for any information.
You can't say "She him/her writes a book" in English, it's incorrect.
"lui" in this sentence is used as a pronoun for an indirect object.
The subject in this sentence is "Il", doing the action through the verb "écrit".
The subject is not always the first element of the sentence, but it's rarely used before the object(s) or the verb(s), except in literature or poetry. Sometimes the verb can come first, or sometimes the subject is implied. For example in interrogative or imperative forms.
How do we know when we put 'lui' ou 'le' ? For example, I know it's je lui vois but when do we put 'le'?
No, it's "je le vois".
"je lui vois" is not correct French.
When the verb is used with an indirect object, like "demander à", we use "lui/leur".
"Je demande à mon père." -> "Je lui demande."
When the verb is used with a direct object, like "demander", we use "le/la/les".
"Je demande un stylo." -> "Je le demande."
Note that some verbs can't be used with indirect objects.
Surely lui is masculine. If it's "her" should it not be Il elle écrit un livre?
Lui can be him or her, and it is an indirect object pronoun. In this case you are writing a book (book being the direct object) to her (the indirect object). As you can't "write her", you have to use the indirect pronoun.
I don't think you would use elle anyway, it would be la or l' if she was the direct object of the verb (as far as I understand it).