Esperanto: A Complete and Comprehensive Grammar/Verbs

Verbs
Esperanto has four aspects, three tenses of indicative mood and three other moods, which can be easily determined by looking at the ending of a verb. Verbs are not conjugated for person or number, only tense or mood.


 * Present tense, with the ending -as. Mi kantas = I sing. Ili parolas = they speak.
 * Past tense -is. Mi kantis = I sang.
 * Future tense -os. Mi kantos = I will sing. Ŝi kuiros = she will cook.
 * Conditional mood -us. Se mi kantus = If I would sing.
 * Volitive mood -u. = Kantu! = Sing! Enlitiĝu! = Go to bed!
 * Infinitive mood -i. Kanti = To sing.

The volitive mood, although primarily used to give commands, is also used to indicate that the subject of the sentence has an obligation or should do something. For instance: Mi tajpu la leteron means "I should type the letter". Compare this to Mi devas tajpi la leteron, which suggests more urgency ("I must type the letter").

The active synthetic forms are: The passive synthetic forms are:

Verbal periphrasis are formed with the adjectival participles plus esti (to be) as the auxiliary verb. The participle reflects aspect and voice, while the verb carries tense or mood:
 * Present progressive: mi estas kaptanta (I am catching [something]), mi estas kaptata (I am caught, I am being caught)
 * Present perfect: mi estas kaptinta (I have caught [something]), mi estas kaptita (I have been caught)
 * Present prospective: mi estas kaptonta (I am going to catch / about to catch), mi estas kaptota (I am going to be caught / about to be caught).

These are not used as often as their English equivalents. For "I am going to the store", you would normally use the simple present mi iras in Esperanto.

The tense or mood of esti can be changed in these periphrastic constructions:
 * mi estis kaptinta (I had caught)
 * mi estus kaptonta (I would be about to catch)
 * mi estos kaptanta (I will be catching).

Although such periphrastic constructions are familiar to speakers of most European languages, the option of contracting [esti + adjective] into a verb is often seen for adjectival participles:


 * mi estas kaptinta or mi kaptintas (I have caught)
 * mi estis kaptinta or mi kaptintis (I had caught)
 * mi estos kaptinta or mi kaptintos (I will have caught).

Volitive and infinitive forms are also found. There is a parallel passive paradigm. A few of these forms, notably -intus and -atas, entered common usage, but most of them are very rare because they are difficult to understand.