Unit 0 - Introduction
Lesson 0.4 - Verb Infinitive, Category, and Stem

Categories of Spanish verbs, their infinitive forms and verb stems.

The stained glass ceiling of the Gran Hotel Ciudad de Mexico

Infinitive Form

The infinitive form of a verb is the generic form, or the way it appears when used without a subject. In English, the infinitive of a verb traditionally includes the word to, such as to sing.

In Spanish, we express the infinitive or dictionary form with just a single word. In Spanish, to sing is simply cantar. Play Audio

Verb Ending

Look at the last two letters of the example cantar. That "-ar" is one of three possible endings of Spanish infinitive verbs. The others are "-er" and "-ir".

An example of each is in the following table:

Spanish Stem Ending Meaning
cantar cant -ar to sing
comer com -er to eat
vivir viv -ir to live

As a result, verbs in Spanish are referred to as -ar, -er, or -ir verbs. The conjugation rules for each type of verb are slightly different.

Of the three categories, verbs that end in -ar are the most common, so when we begin looking at conjugations in the next unit, we will begin there.

Verb Stem

To form conjugations, we need the verb's stem. To get the stem, simply remove the two-letter ending from the infinitive. What is left over is the verb stem.

Examples of those are in the table above as well.

For cantar, conjugations are formed by taking the verb stem "cant" and adding other endings to indicate which form the verb is taking. In Unit 1, you will begin learning the endings for the various tenses.