Spanish verbs form one of the more complex areas of Spanish grammar. Spanish is a relatively synthetic language with a moderate to high degree of inflection, which shows up mostly in Spanish conjugation.
As is typical of verbs in virtually all languages, Spanish verbs express an action or a state of being of a given subject, and like verbs in most Indo-European languages, Spanish verbs undergo inflection according to the following categories:
- Tense: past, present, or future
- Number: singular or plural
- Person: first, second or third
- T–V distinction: familiar or formal
- Mood: indicative, subjunctive, or imperative
- Aspect: perfective or imperfective (distinguished only in the past tense as preterite and imperfect)
- Voice: active or passive
The modern Spanish verb paradigm (conjugation) has 16 distinct complete[1] forms (tenses), i.e. sets of forms for each combination of tense, mood and aspect, plus one incomplete[2] tense (the imperative), as well as three non-temporal forms (the infinitive, gerund, and past participle). Two of the tenses, namely both subjunctive futures, are now obsolete for most practical purposes.
The 16 "regular" forms (tenses) include 8 simple tenses and 8 compound tenses. The compound tenses are formed with the auxiliary verb haber plus the past participle. Verbs can be used in other forms, such as the present progressive, but in grammar treatises they are not usually considered a part of the paradigm but rather periphrastic verbal constructions.