Je donne un cadeau à Jeanne
In the french tree, in the "at work 3" course. There is a part in the end, "Je donne un cadeau à Jeanne", i still don't understand that. Can someone please explain why we have to use "Nous donnons une lettre à Émilie" and can't use " Nous donnons Emilie une lettre" ?
You're translating too literally, different languages have different word orders and the verb "donner" uses a preposition "à" for the indirect object.
In French, indirect objects always need that preposition there. There is not the flexibility like in English to suppress the preposition depending on word order.
We gave a letter to Emily.
We gave Emily a letter. ←preposition (to) suppressed
On a donné une lettre à Émilie.
On a donné à Émilie une lettre. ←preposition (à) must remain
Also know that the second word order above, with the indirect object first, is not as common as in English, at least in my experience.
My French is not as good as my Spanish, but they work the same in a lot of ways.
I think it's because you are not giving Emilie (to someone else).
I think you have to follow the verb with the item you're giving.
You can say "Nous lui donnons une lettre" but if you are specifying a person by name, you have to use the "à".
I don't know why for sure and I didn't make the rules but that is one that I have learned. In case of question, just use the "à....", as it works for pronouns and names. Just be sure to put in the "t" if saying "to her" ("à-t-elle")
It's not just names. Indirect objects, when not replaced by pronouns, always keep their prepositions in French. That's how we identify them as indirect, as opposed to direct, objects. We can't rely on word order as we sometimes can in English.
And there is no such thing as "à-t-elle". You are confusing two different concepts. The "-t-" appears when certain verbs are inverted with their subjects to make a question. It has nothing to do with prepositions.
Elle a donné la lettre à Émilie.
A-t-elle donné la lettre à Emilie ?
If for whatever reason you need to use "à" with the tonic pronoun "elle", you don't add the "-t-" in between. It's is simply "à elle".
The logic is the same as English, as in "I am giving a present to Jeanne."