The infinitive is the basic form of the verb, the one that appears in the dictionary: hablar, comer, vivir. In regular verbs, the infinitive ends in -ar, -er or -ir. To find the verbal root, the ending is removed: habl- in hablar, com- in comer, viv- in vivir. The root is the part that preserves the main meaning and to which the conjugation endings are added. If you change the ending, you change the person, the number and the tense, as in Presente simple.

The verb changes according to the person and the number. In singular they are yo, tú and él / ella / usted. In plural they are nosotros / nosotras, vosotros / vosotras and ellos / ellas / ustedes. Each verbal form carries a different ending for each combination. Yo does the action; tú you do it; él / ella / usted does it for a single person; nosotros / nosotras do it together; vosotros / vosotras do it among several in Spain; ellos / ellas / ustedes do it for several people. These persons are the basis to conjugate any regular verb in the present and also to recognize forms in other tenses like the Pretérito and the Imperfecto.

Regular verbs ending in -ar form the present indicative with this root + ending: -o, -as, -a, -amos, -áis, -an. With hablar, the conjugation becomes: hablo, hablas, habla, hablamos, habláis, hablan. The root does not change and the endings are added directly. This model applies to thousands of verbs like trabajar, estudiar and escuchar. When an auxiliary verb construction appears, the conjugated form of the main verb will follow this pattern if it is regular. In Presente simple this same scheme is used to talk about habitual actions and current facts.

Regular verbs ending in -er use these endings in the present indicative: -o, -es, -e, -emos, -éis, -en. With comer, the full form is como, comes, come, comemos, coméis, comen. The root remains fixed: com-. Verbs like aprender, beber and vender follow the same pattern. In contrast with -ar verbs, here the endings change, but not the way the root is formed. These forms appear frequently in everyday conversations and also in compound tenses, where the main verb retains its regular participle.

Regular verbs ending in -ir are conjugated in the present with -o, -es, -e, -imos, -ís, -en. With vivir, the forms are vivo, vives, vive, vivimos, vivís, viven. The root remains the same: viv-. This model applies to verbs like escribir, abrir and recibir. Many -ir forms resemble -er forms in several persons, but in nosotros and vosotros they use their own endings. When language needs to express an action in progress, these regular forms combine with the Presente Progresivo.

The regular gerund is formed with the verb root + -ando for -ar verbs and with the verb root + -iendo for -er and -ir verbs. Thus, hablar becomes hablando, comer becomes comiendo and vivir becomes viviendo. The gerund does not change according to the person. It is used mainly with an auxiliary verb to express an action in progress, as in estoy hablando, estás comiendo or están viviendo. In these constructions, the auxiliary carries the conjugation and the gerund provides the idea of ongoing action.

The regular participle is formed with the verb root + -ado for -ar verbs and with the verb root + -ido for -er and -ir verbs. That is why forms like hablado, comido and vivido appear. The participle does not change for person either. It is used in compound tenses with the auxiliary verb haber: he hablado, has comido, han vivido. It also appears as an adjective in expressions like la puerta cerrada or el trabajo terminado, although in regular verbs the base form remains the same.

In everyday speech, regular verb forms serve to count actions, describe states and place events in time. The present expresses habits, general truths and actions that occur now. The gerund appears in simple periphrases for an action in development, such as estoy trabajando or siguen estudiando. The participle appears in compound tenses with haber and forms structures like he comido or hemos salido. These combinations allow building clear messages about what is happening, what has happened and what is happening at this moment.