If it was leo the translation would be "I need I read a book" whereas with the infinitive conjugated leer, "to read", it is "I need to read a book"
its Basically the same as English, you would not say "he must goes...". Here necesitar is conjugated so the next verb is given in infinitive. Technically its a bit more complicated than this tbh.
I believe adding r to the end of read, write, etc... Tells us TO read, TO write...
If there are two verbs, the first verb is conjugated while the second one is in the infinitive form. This also applies in English.
In this case, "LEER" is the 2nd verb. The 1st one is "NECESITAR" --> "Necesito".
When you have "to..." verbs you translate them in infinitive "leer"=to read "comer"=to eat example: necesito comer= I need TO READ
Hey, so is it pronounced ''libro'' or ''livro'' or is it something in between?