3.4 Fourth conjugation

Characteristics of Fourth Conjugation

Fourth conjugation verbs are one of the four main verb groups in Latin. You can spot them by their infinitive ending in -ire (like audire, "to hear"). Their stem vowel is -i-, which shows up consistently across most forms and makes them fairly predictable once you learn the pattern.

Principal Parts

Like all Latin verbs, fourth conjugation verbs have four principal parts. Here's the standard pattern using audio as a model:

The -ire infinitive ending (2nd part) is the clearest way to identify a fourth conjugation verb in a dictionary entry. Compare this with -āre (1st), -ēre (2nd), and -ere (3rd).

Stem Vowel -ī-

The -ī- stem vowel is what ties fourth conjugation forms together. It appears before the personal endings in the present tense, stays visible in the imperfect and future, and carries through into participles and infinitives. Keeping your eye on that -ī- is the single best way to recognize these verbs in any form.

Present Tense Forms

The present tense expresses actions happening now or habitually. To form it, take the present stem (e.g., audī-) and add the personal endings. Notice that the -i- appears throughout, but lengthens to -iu- in the 3rd person plural.

Active Voice

Two forms to watch: the 1st person singular ends in -iō (not just -ō), and the 3rd person plural ends in -iunt (not -int or -unt).

Passive Voice

The 2nd person singular passive can also appear as audīre (an alternate form). Again, the 3rd person plural uses -iuntur, matching the -iu- pattern from the active.

Imperfect Tense Forms

The imperfect expresses ongoing or repeated actions in the past ("was hearing," "used to hear"). Fourth conjugation forms the imperfect the same way as every other conjugation: attach the tense sign -ēba- to the present stem.

Formation Steps

1. Take the present stem: audī-
2. Add the imperfect tense sign: -ēba-
3. Add personal endings: -m, -s, -t, -mus, -tis, -nt (active) or -r, -ris, -tur, -mur, -minī, -ntur (passive)

This gives you: audiēbam, audiēbās, audiēbat, audiēbāmus, audiēbātis, audiēbant

The -ī- of the stem stays visible right before -ēba-, so these forms are easy to spot.

Examples in Context

• Audiēbam carmina. (I was listening to songs.)
• Puerī veniēbant ad scholam. (The boys were coming to school.)
• Urbs muniēbātur ā mīlitibus. (The city was being fortified by soldiers.)
• Custōdēs portās aperiēbant. (The guards were opening the gates.)

Future Tense Forms

The future tense expresses actions that will happen. Fourth conjugation verbs form the future differently from 1st and 2nd conjugation verbs (which use -bō, -bis, etc.). Instead, fourth conjugation uses -a- and -ē- markers, just like 3rd conjugation.

Formation Steps

1. Take the present stem: audī-
2. For the 1st person singular, add -am: audiam
3. For all other forms, add -ē- plus personal endings: audiēs, audiet, audiēmus, audiētis, audient

Here's the full active paradigm:

For the passive, swap in passive endings: audiar, audiēris, audiētur, audiēmur, audiēminī, audientur.

Comparison with Other Conjugations

• 1st and 2nd conjugation use -bō, -bis, -bit... for the future.
• 3rd and 4th conjugation both use -am, -ēs, -et... for the future.
• The difference between 3rd and 4th conjugation futures is the stem vowel: audiam (4th, from audī-) vs. regam (3rd, from reg-). In practice, the 4th conjugation keeps its -i- visible before the future marker.

Perfect Tense Forms

The perfect tense expresses completed past actions. Fourth conjugation verbs form the perfect system (perfect, pluperfect, future perfect) from the 3rd principal part stem.

Regular vs. Irregular Perfects

Most fourth conjugation verbs form the perfect regularly by adding -īvī to the stem:

• audiō → audīvī (I heard / I have heard)
• dormiō → dormīvī (I slept)

Some verbs contract the perfect by dropping the -v-: audīvī → audiī. Both forms are correct.

Other verbs have irregular perfect stems that you need to memorize:

• veniō → vēnī (I came)
• sentiō → sēnsī (I felt)
• inveniō → invēnī (I found)

The personal endings for the perfect are always the same across all conjugations: -ī, -istī, -it, -imus, -istis, -ērunt (or -ēre).

Translation Considerations

The Latin perfect can translate as either the English simple past ("I heard") or the present perfect ("I have heard"). Context determines which works better. If the sentence describes a one-time completed event, use simple past. If the result still matters in the present, present perfect often fits better.

Common Fourth Conjugation Verbs

These are verbs you'll encounter constantly. Memorize their principal parts, especially the irregular ones.

Deponent Verbs

Some fourth conjugation verbs are deponent: they have passive forms but active meanings. You conjugate them in the passive voice, but translate them as active.

• partior, partīrī, partītus sum (to divide, share)
• mentior, mentīrī, mentītus sum (to lie)
• experior, experīrī, expertus sum (to try, experience)
• orior, orīrī, ortus sum (to rise, be born)

These still follow fourth conjugation patterns in their endings. The key difference is that they have no active forms, and their 3rd principal part is a perfect passive participle used with sum.

Imperative Mood

The imperative expresses direct commands. Fourth conjugation imperatives are straightforward.

Formation and Usage

• Singular (commanding one person): use the present stem as-is → audī (hear!)
• Plural (commanding multiple people): add -te to the stem → audīte (hear!)

You'll find imperatives in dialogue, speeches, and instructions.

Negative Commands

Latin doesn't just stick nōn in front of an imperative. Instead, negative commands use nōlī (singular) or nōlīte (plural) followed by the present infinitive:

• Nōlī audīre. (Don't listen! — to one person)
• Nōlīte audīre. (Don't listen! — to multiple people)

Nōlī/nōlīte literally means "be unwilling," so the construction is "be unwilling to hear." There's also a more literary construction using nē + perfect subjunctive for prohibitions, but the nōlī form is far more common.

Infinitives

Fourth conjugation verbs have six infinitive forms across three tenses and two voices.

Present Infinitives

• Present active: stem + -īre → audīre (to hear)
• Present passive: stem + -īrī → audīrī (to be heard)

These appear frequently in indirect statements and as complements to verbs like possum (to be able) or volō (to want).

Perfect and Future Infinitives

• Perfect active: perfect stem + -isse → audīvisse (to have heard)
• Perfect passive: 4th principal part (agreeing in gender/number/case) + esse → audītum esse (to have been heard)
• Future active: future active participle (4th part stem + -ūrus/-a/-um) + esse → audītūrum esse (to be about to hear)
• Future passive: supine (4th principal part) + īrī → audītum īrī (to be about to be heard)

The future passive infinitive is rare. Focus your energy on the present and perfect forms, which show up much more often.

Participles

Participles are verbal adjectives. They have tense and voice like verbs, but they decline like adjectives and modify nouns.

Present Active Participle

Formed by adding -iēns, -ientis to the present stem:

• audiēns, audientis (hearing)

This declines as a 3rd declension adjective (one-termination type). It describes an action happening at the same time as the main verb: Puer audiēns cantābat (The boy, hearing [while hearing], was singing).

Perfect Passive Participle

This is the 4th principal part of the verb:

• audītus, -a, -um (having been heard)

It declines like a 1st/2nd declension adjective (like bonus, -a, -um). It describes a completed action: Vōx audīta clāra erat (The voice, having been heard, was clear). Combined with forms of sum, it creates the passive perfect system (audītus est = he was heard).

Subjunctive Mood

The subjunctive expresses wishes, possibilities, purposes, and appears in many types of subordinate clauses. Fourth conjugation has distinct subjunctive forms for each tense.

Present Subjunctive

The present subjunctive is formed by changing the stem vowel -ī- to -iā-, then adding personal endings:

audiam, audiās, audiat, audiāmus, audiātis, audiant

A helpful mnemonic for remembering subjunctive vowels across all conjugations: "wE fEAR A LIAr." The vowels (ē, eā, a, iā) correspond to the subjunctive markers for 1st, 2nd, 3rd, and 4th conjugations respectively.

Watch out: the present subjunctive audiam looks identical to the future indicative audiam. Context (especially the type of clause) tells you which one you're dealing with.

Imperfect Subjunctive

The imperfect subjunctive has a convenient formation rule:

1. Take the present active infinitive: audīre
2. Add personal endings directly to it: -m, -s, -t, -mus, -tis, -nt

Result: audīrem, audīrēs, audīret, audīrēmus, audīrētis, audīrent

This trick works for every conjugation. The imperfect subjunctive appears in contrary-to-fact conditions, purpose clauses in past-tense sentences, and indirect questions referring to past time.

Compound Verbs

Many common Latin verbs are compounds: a prefix attached to a simple fourth conjugation verb. The prefix modifies the meaning, but the verb still conjugates as fourth conjugation.

Common Prefixes with Fourth Conjugation

How Prefixes Change Meaning

Prefixes can shift a verb's meaning in predictable ways. Veniō means "to come," but inveniō means "to find" (literally "to come upon"). Perveniō means "to arrive" (to come through to a destination). Recognizing these prefix patterns helps you figure out unfamiliar compound verbs without a dictionary.

Some prefixes also change whether a verb takes a direct object. Veniō is intransitive (you come to a place), but inveniō is transitive (you find something).

Fourth Conjugation vs. Third Conjugation i-Stems

This is one of the trickiest distinctions in Latin verb classification. Third conjugation i-stem verbs (like capiō, capere) look a lot like fourth conjugation verbs in some forms, but they belong to different conjugations and behave differently.

How to Tell Them Apart

The most reliable test is the infinitive: if the 2nd principal part ends in -īre, it's 4th conjugation. If it ends in -ere (short e), it's 3rd conjugation i-stem.

Common Confusions

Verbs like capiō (to take), faciō (to make), and fugiō (to flee) are 3rd conjugation i-stems, not 4th conjugation. Their 1st person singular (-iō) and 3rd person plural (-iunt) look like 4th conjugation, but the infinitive gives them away: capere, not capīre. Always check the dictionary entry's 2nd principal part when you're unsure.

Translation Strategies

Identifying Fourth Conjugation Verbs

When you encounter an unfamiliar verb, follow these steps:

1. Look at the dictionary entry for the 2nd principal part. Does it end in -īre? If yes, it's 4th conjugation.
2. In a passage, look for the characteristic -ī- before endings. Forms like audiēbat, audīmus, or audient all show that telltale vowel.
3. Watch for the -iō ending in the 1st person singular and -iunt in the 3rd person plural present. But remember to confirm with the infinitive, since 3rd i-stems share these forms.

Using Context Clues for Tense

Once you've identified the verb as 4th conjugation, determine its tense by examining:

• Tense markers in the form itself: -ēba- (imperfect), -ēri- (future), -isse (perfect infinitive), etc.
• Time words nearby: adverbs like iam (now/already), olim (once), crās (tomorrow) help confirm tense.
• The sequence of tenses in complex sentences: if the main verb is past tense, subordinate subjunctives typically shift to imperfect or pluperfect.
• Narrative context: is the author describing background action (imperfect), a completed event (perfect), or something yet to happen (future)?