This is not a complete list of verbal tenses found in all languages. It focuses on tenses that are expressed synthetically, i.e. using affixes in one word (as opposed to analytical expression, using combination of a main verb and an auxiliary verb). Morphological / part-of-speech tags usually only need to distinguish synthetical verb forms.

• infinitive
• finite verb
  • indicative
    • future
    • present
    • past
      • aorist
      • imperfect
      • perfect
      • pluperfect
  • imperative
  • subjunctive
  • jussive
• participle
  • present
  • past
  • passive
• transgressive
• gerund
• supine

Usually considered base form of the verb, appears in dictionaries. In text it appears as part of analytical verb forms and as argument of other words:

• future tense: bude dělat, er wird kommen
• argument of modal verb: musí dělat, er muss machen, he must do
• argument of some other verbs, subordinating conjunctions etc.: potřebuje odejít, er kommt um das zu beenden, he let us to do it, his intention to finish this

In some languages infinitive is marked by verb affixes:

• Czech infinitive ends in -t, -ti, -ct, -ci: dělat, dělati, říct, říci
• German infinitive ends in -en: machen, sagen

In some languages, the morpheme marking infinitive is separate word (English to). In English, the base form of the verb is not (full) infinitive. It becomes infinitive when combined with the infinitive mark (to do, to say). Without the mark, it can be used (in English) as imperative.

Both approaches can be combined. Although infinitives are recognizable by the -en suffix in German, the infinitive mark zu is used with infinitives in some contexts. Depending on the verb, zu is either a separate word, or a morpheme inserted between the verb prefix and stem (zu beenden vs. anzupassen).

• English infinitive mark is to
• German infinitive mark is zu
• Danish infinitive mark is at
• Swedish infinitive mark is att

In DZ Interset, infinitive is decoded as verbform = inf. This value is set even for the English base verb form, although it is not certain whether the form is used as infinitive, or imperative. Mood, tense and voice are usually empty. Czech infinitives set the feature negativeness. Portuguese infinitives can be mildly conjugated. I think I may have seen active/passive infinitives but I am not sure where.

Finite verb forms are those most frequently used. They are classified according to mood: the most ordinary mood is indicative, most languages also have imperative, some also have subjunctive and jussive.

Opposed to finite verbs are non-finite verb forms, namely infinitive, supine, participle, transgressive and gerund.

In DZ Interset, finite verb form is decoded as verbform = fin.

Verbs in indicative mood merely indicate that someone performs / has performed / will perform the action of the verb. Opposed to indicative is imperative (the verb orders the listener to perform the action) and various conditional constructions (the action would be performed if…)

There is a multitude of indicative verb forms, classified according to tense (present, past, future etc.) and voice (active or passive). Present active forms are the default. They are usually the simplest, formed synthetically. Other tenses and voices are formed synthetically or analytically, depending on language.

In DZ Interset, indicative is decoded as mood = ind. This is also the default mood value for finite verb forms. (For non-finite verb forms, default mood is empty.)

Verbs in present tense indicate an action that is taking place at the time of speaking, or in a general timespan (“usually”). They are usually formed synthetically, and take different forms according to person and number, possibly also gender. If two verbs use different morphemes to express the same combination of person, number, gender etc., they are assigned to different conjugation classes. Example: Czech verb nést:

In DZ Interset, present tense is decoded as tense = pres.

Czech verbs are divided lexically to perfective and imperfective. Present tense forms of perfective verbs are in fact forms of future tense. If the physical tagset encodes these forms as present, they will be decoded into Interset as tense = pres. However, if the physical tagset contains the information that these are semantically future forms, it will be decoded as tense = fut.

The English progressive present tense (he is doing) is formed analytically by the simple present form of the auxiliary verb to be and the present participle (gerund) of the main verb. There is thus no Interset feature value for this tense. See participle and gerund.

Simple past indicates action that took place in past. Some languages (e.g. Czech) have only this one past tense. Others have more refined tense system that allow to express whether the action has been completed (perfect) or not (imperfect), whether it was running while something else was being done etc. In Czech however, the perfect/imperfect aspect is lexically inherent, so that past perfect is replaced by simple past tense of a perfective verb.

Czech past tense is formed by past participle of the main verb and (in 1st and 2nd person only) present form of the auxiliary verb být. The participle is decoded with tense = past.

German imperfect past tense (Präteritum) is formed synthetically. Perfect past tense (Perfekt) is formed analytically by present form of the auxiliary verb haben and past participle of the main verb. Pluperfect past tense (Plusquamperfekt) is formed analytically by imperfect past form of the auxiliary verb haben and past participle of the main verb. The imperfect past forms and the participle are decoded with tense = past.