The ending -i indicates the infinitive, for example ami (to love). This is the neutral form found in a dictionary. It is most often used to complement the verbs povas (can), volas (want), devas (must), and ŝatas (like). For example:<pre>
Mi volas danci. = I want to dance. Mi ŝatas manĝi. = I like to eat. Ĉu vi povas fari tion? = Can you do that?</pre>
Yeah, I understand how to differentiate between indirect and direct objects because of my time with Spanish, I am just having a hard time thinking of why it should be direct with this specific verb. Could you give me an example of the same verb (telefoni) but with both a direct and an indirect object? Are you saying that it works like "to say" but in the context of a telephone call?
"telefoni" is a transitive verb and comes from a Romance Language (it helps you know that it's got a very close relation with the French verb "telephoner" or "telefon(e)ar" in Spanish.
"Ili ne povas telefoni al ni" sounds very strange, but Esperanto is an universal language, so you can express the same idea with a very "Germanic" syntax. So, **Ili ne povas telefoni nin" sounds a great deal better than ".. al ni".
I'm looking at my comment from 9 months ago and wondering what was going through my mind. I'm not sure how I got from "telefoni" to "diri".
That said, I honestly don't know if it's grammatical in Esperanto to treat "telefoni" like a regular transitive verb or if it requires a prepositional phrase. Assuming it can go either way, it would just be a matter of:
Ili telefonas nin.
Ili telefonas al ni.
In general, accusatives don't come after prepositions, because prepositions usually modify indirect objects.
The verb's action happens in relation to the indirect object, while it acts directly on the direct object.
(There are some exceptions, which you'll see later.)
"Telefoni" is strictly "to call by telephone".
Zamenhof did not speak English, and even if he did, he developed Esperanto long before the idiom "to call someone out" existed. And even then, I'm pretty sure the whole point of Esperanto is for broad communication. Why would he include a highly idiomatic expression that's unique to English?