Verbs that require indirect pronouns
The following verbs are always used with indirect pronouns:
to read to leggere
to write to scrivere
to bring portare
to say/tell dire
to teach insegnare
to give (as a gift) regalare
to demand (ask) domandare
to prepare preparare
to lend prestare
to return, give back restituire
to bring back riportare
to send mandare
to answer rispondere
to show mostrare
to offer offrire
to call/telephone telefonare
There are others, but these will serve as good examples.
This is where those "Clitics" lessons, that you know and love, come into play.
The indirect pronouns are Mi, Ti, Gli, Le, Ci, Vi, and Loro, and they can often be placed at the end of a verb (e.g. "Offrirti" or "Dimmi") or at the beginning-- which is how Duolingo starts you out in the Clitics lesson (e.g. "Ti mostro" or "Le diciamo").
If you get into the habit of adding the word "to" (or "for", sometimes) during translation, when you see an indirect pronoun, then the list of verbs shown above makes a lot more sense if you're asking yourself, "Why those verbs?".
Thus: Gli = "to him" (or "for him"); Le = "to/for her", and so on.
All of those verbs are implicitly asking a question, which is framed as, "To whom?" and answered with "To me" (or to them, or to her, etc.).
Now translate these four sentences, using the same word order that they appear in:
Mi legge questo libro.
Ti scrivo una lettera.
Gli dice la risposta.
Le insegna una nuova parola.
To me she reads this book; You read (to) me this book .
To you I write a letter; I write a letter to you .
To him she tells the answer; She tells (to) him the answer .
To her he teaches a new word; He teaches (to) her a new word .
You can see that the common English way of speaking often leaves out the word "to", but if the word "to" is placed at the beginning of the sentence then it is required, even in English-- one would never say "Me she reads this book, for instance.
You can also see that the word "for", instead of "to", could be substituted easily in certain verb cases-- For you I bring a sandwich/ I bring a sandwich for you.
Many other verbs that are not on that list do not make any sense if you use an indirect pronoun. Take vedere as an example:
To him I see. I see (to) him .
No; that sounds silly. How about...
Lo vedo? Him I see. I see him .
That's better. I used the direct pronoun (do not say or think "to" in front of them), instead of the indirect, and it worked perfectly.
So, in this way, the Italian manner of speaking makes more sense than English does!