An infinitive is the raw, unconjugated form of a verb. It is essentially the verb in its "dictionary" state, like "to talk" or "to work." In Spanish, every single verb belongs to one of three families based on its ending: -ar, -er, or -ir. Today, we are focusing entirely on the largest and friendliest family: verbs that end in -ar.

To start using these verbs, we perform a simple linguistic surgery. Think of a verb like hablar (to speak) or trabajar (to work) as having two distinct parts: the ending (-ar) and the stem (the base part that carries the actual meaning). By slicing off the -ar ending, you isolate the stems habl- and trabaj-.

Keeping this stem pristine and untouched is the secret key to conjugating regular verbs. Once you have isolated this solid foundation, you will use it as a reliable anchor to attach different endings later on, without ever changing a single letter of the stem itself. Let's make sure you can isolate a stem before we move forward.