Editing Latin conjugation (section)

=== Fourth conjugation ===
The fourth conjugation is characterized by the vowel ī and can be recognized by the -īre ending of the present active infinitive. Deponent verbs have the infinitive -īrī:
{| class="wikitable" style="width: 55em;"
|-
!
!
!colspan="3"|Indicative
!
!colspan="2"|Subjunctive
|-
!
||||'''Present'''||'''Future'''||'''Imperfect'''||||'''Present'''||'''Imperfect'''
|-
!rowspan=2|Active
||||''I hear''||''I will hear''||''I was hearing'' || ||''I may hear''||''I might hear''
|-
|''I<br />you sg.<br />he, she, it<br />we<br />you pl.<br />they''
|'''{{lang|la|audiō<br />audīs<br />audit<br />audīmus<br />audītis<br />audiunt|italic=no}}'''
|'''{{lang|la|audiam<br />audiēs<br />audiet<br />audiēmus<br />audiētis<br />audient|italic=no}}'''
|'''{{lang|la|audiēbam<br />audiēbās<br />audiēbat<br />audiēbāmus<br />audiēbātis<br />audiēbant|italic=no}}'''
|
|'''{{lang|la|audiam<br />audiās<br />audiat<br />audiāmus<br />audiātis<br />audiant|italic=no}}'''
|'''{{lang|la|audīrem<br />audīrēs<br />audīret<br />audīrēmus<br />audīrētis<br />audīrent|italic=no}}'''
|-
!
|-
!rowspan=2|Passive
||||''I am heard''||''I will be heard''||''I was being heard'' || || ''I may be heard''|| ''I might be heard''
|-
|''I<br />you sg.<br />he, she, it<br />we<br />you pl.<br />they''
|'''{{lang|la|audior<br />audīris<br />audītur<br />audīmur<br />audīminī<br />audiuntur|italic=no}}'''
|'''{{lang|la|audiar<br />audiēris/re<br />audiētur<br />audiēmur<br />audiēminī<br />audientur|italic=no}}'''
|'''{{lang|la|audiēbar<br />audiēbāris/re<br />audiēbātur<br />audiēbāmur<br />audiēbāminī<br />audiēbantur|italic=no}}'''
|
|'''{{lang|la|audiar<br />audiāris/re<br />audiātur<br />audiāmur<br />audiāminī<br />audiantur|italic=no}}'''
|'''{{lang|la|audīrer<br />audīrēris/re<br />audīrētur<br />audīrēmur<br />audīrēminī<br />audīrentur|italic=no}}'''
|-
|}

Other forms:

*Infinitive: '''{{lang|la|audīre|italic=no}}''' "to hear"
*Passive infinitive: '''{{lang|la|audīrī|italic=no}}''' "to be heard"
*Imperative: '''{{lang|la|audī!|italic=no}}''' (pl. '''{{lang|la|audīte!|italic=no}}''') "hear!"
*Future imperative: '''{{lang|la|audītō!|italic=no}}''' (pl. '''{{lang|la|audītōte!|italic=no}}''') "hear! (at a future time)" 
*Passive imperative: '''{{lang|la|audīre!|italic=no}}''' (pl. '''{{lang|la|audīminī!|italic=no}}''') "be heard!" (usually only found in deponent verbs)
*Present participle: '''{{lang|la|audiēns|italic=no}}''' (pl. '''{{lang|la|audientēs|italic=no}}''') "hearing"
*Future participle: '''{{lang|la|audītūrus|italic=no}}''' (pl. '''{{lang|la|audītūrī|italic=no}}''') "going to hear"
*Gerundive: '''{{lang|la|audiendus|italic=no}}''' (pl. '''{{lang|la|audiendī|italic=no}}''') "needing to be heard"
*Gerund: '''{{lang|la|audiendī|italic=no}}''' "of hearing", '''{{lang|la|audiendō|italic=no}}''' "by /for hearing", '''{{lang|la|ad audiendum|italic=no}}''' "in order to hear"

Principal parts of verbs in the fourth conjugation generally adhere to the following patterns:

* The perfect has suffix ''-vī''. Verbs which adhere to this pattern are considered to be "regular". Examples:
** {{lang|la|audiō, audīre, audīvī, audītum}} "to hear, listen (to)"
** {{lang|la|custōdiō, custōdīre, custōdīvī, custōdītum}} "to guard"
** {{lang|la|dormiō, dormīre, dormīvī (dormiī), dormītum}} "to sleep"
** {{lang|la|impediō, impedīre, impedīvī, impedītum}} "to hinder, impede"
** {{lang|la|mūniō, mūnīre, mūnīvī, mūnītum}} "to fortify, to build"
** {{lang|la|pūniō, pūnīre, pūnīvī, pūnītum}} "to punish"
** {{lang|la|sciō, scīre, scīvī, scītum}} "to know"

* The perfect has suffix ''-uī''. Examples:
** {{lang|la|aperiō, aperīre, aperuī, apertum}} "to open, to uncover"

* The perfect has suffix ''-sī'' (''-xī'' when ''c'' comes at the end of the root). Examples:
** {{lang|la|saepiō, saepīre, saepsī, saeptum}} "to surround, to enclose"
** {{lang|la|sanciō, sancīre, sānxī, sānctum}} "to confirm, to ratify"
** {{lang|la|sentiō, sentīre, sēnsī, sēnsum}} "to feel, to perceive"
** {{lang|la|vinciō, vincīre, vīnxī, vīnctum}} "to bind"

* The perfect has suffix ''-ī'' and reduplication. Examples:
** {{lang|la|reperiō, reperīre, repperī, repertum}} "to find, discover"

* The perfect has suffix ''-ī'' and vowel lengthening in the stem. Examples:
** {{lang|la|veniō, venīre, vēnī, ventum}} "to come, to arrive"
** {{lang|la|inveniō, invenīre, invēnī, inventum}} "to find"

Deponent verbs in the 4th conjugation include the following:<ref>Gildersleeve & Lodge Latin Grammar (1985), §166.</ref>
:*{{lang|la|assentior, assentīrī, assēnsus sum}} "to assent"
:*{{lang|la|experior, experīrī, expertus sum}} "to experience, test"
:*{{lang|la|largior, largīrī, largītus sum}} "to bestow"
:*{{lang|la|mentior, mentīrī, mentītus sum}} "to tell a lie"
:*{{lang|la|mētior, mētīrī, mēnsus sum}} "to measure"
:*{{lang|la|mōlior, mōlīrī, mōlītus sum}} "to exert oneself, set in motion, build"
:*{{lang|la|potior, potīrī, potītus sum}} "to obtain, gain possession of"
:*{{lang|la|sortior, sortīrī, sortītus sum}} "to cast lots"

The verb {{lang|la|orior, orīrī, ortus sum}} "to arise" is also regarded as 4th conjugation, although some parts, such as the 3rd singular present tense {{lang|la|oritur}} and imperfect subjunctive {{lang|la|orerer}}, have a short vowel like the 3rd conjugation. But its compound {{lang|la|adorior}} "to rise up, attack" is entirely 4th conjugation.

In the perfect tenses, shortened forms without ''-v-'' are common, for example, '''{{lang|la|audīstī, audiērunt, audierat, audīsset|italic=no}}''' for {{lang|la|audīvistī, audīvērunt, audīverat, audīvisset}}. Cicero, however, prefers the full forms {{lang|la|audīvī, audīvit}} to {{lang|la|audiī, audiit}}.<ref name=":1"/>