How come the unconjugated forms of verbs in English have a "to" in them while in other languages they are just a variation on the verb in question?
In English the verbs "to learn" and "to write" are
conjugations. They are conjugations of the base form verbs "learn" and "write."
At least in Spanish, "aprender" and "escribir" aren't variations of the basic forms. They are the basic forms.
It's interesting what Wikipedia holds about the infinitive of English verbs, that they are the basic forms with or without the particle "to," so "learn" and "write" have the same meaning as "to learn" and "to write" respectively. But that generalization is imprecise when translating to and from another language. "Learn" and "write" are more precisely translated into Spanish as the second person informal imperative "aprende," and "escribe"--(you) learn or learn you, (you) write or write you (as it might have been said in some of the older urban dialects of the US "listen you!") --respectively. From Spanish, "aprender" and "write" are more precisely translated as "to learn" and "to write" respectively, as they don't have other conjugational meanings in Spanish.