The Verb: from the latin word Verbum = word, meaning the word (the verb) is the most important thing in every sentence, so we can collect from it a lot of information:
The root gives us the meaning of the verb and through it we can answer the question What?, What are we talking about? Aprender (learning).
However, most of the information is in the ending. From these few letters we can find out: the person, answering the question Who? Nosotros (We)
We can also deduce the tense from the verb ending, answering the question When? Ahora (Now).
Finally, we are able to know the verbal mood and answer the question How? Indicative mood: real situation.
Basically, we can say that the verb is the one that indicates which action the grammatical subject of a sentence does and it can express moods, feelings, actions, attitudes or states.
We give you a second example:
What? from bailar (dance)
When? Conditional future
How? Subjunctive mood, non real situation
Hoy nevará toda la tarde (Today it will snow all day)
Anoche llovió muy fuerte (Last night it rained very hard)