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are verbs. The inflection of verbs is called conjugation . The changes in verb endings indicate person (first, second, or third person), tense (time of action), voice (active or passive 2 ), and mood (indicative, subjunctive, or imperative 3 ).
    Almost every Latin verb has four stems (called principal parts), each of which has a different function, and from which are formed all the possible tenses, and voices. For example,
    amo-amare-amavi-amatum = love
amo = I love (first person singular, present tense, active voice)
amamus = we love (first person plural, present tense, active voice)
amavi = I have loved (first person singular, perfect tense, active voice)
amabitur = She (or he or it) will be loved (third person singular, future tense, passive voice)
amata eras = you (fem.) had been loved (second person singular, pluperfect tense, passive voice)
amatē = love! (imperative)
    amare = to love (infinitive)
    CONJUGATIONS
    There are four conjugations, each of which is distinguished by the vowel that appears in the infinitive form:
     
The first conjugation is distinguished by a in the infinitive form:
    amo-am a re-amavi-amatum = love
    porto-port a re-portavi-portatum = carry
The second conjugation is distinguished by ē (long) in the infinitive form:
    moneo-monēre-monui-monitum = warn
    teneo-tenēre-tenui-tentum = hold
The third conjugation is distinguished by ě (short) in the infinitive form:
    duco-duc e re-duxi-ductum = lead
    facio-fac e re-feci-factum = make
The fourth conjugation is distinguished by i in the infinitive form:
    audio-aud i re-audivi-auditum = hear
    venio-ven i re-veni-ventum = come
    FINDING THE STEM OF A LATIN VERB
    Almost all English derivatives from Latin verbs are formed either from the present infinitive stem (which is the infinitive minus the -re ending) or from the perfect passive stem (the fourth principal part minus the -um ending. 4 ) Very often, when a suffix is added to the present stem of a verb (see next chapter), the distinguishing vowel of the conjugation is also dropped before the suffix is added.
     
Present Infinitive
Present Stem
Perfect Passive 5
Perfect Stem
portare (to carry)
porta-
portatum
portat-
monēre (to warn)
monē-
monitum
monit-
tenēre (to hold)
tenē-
tentum
tent-
ducere (to lead)
duce-
ductum
duct-
agere (to do)
age-
actum
act-
facere (to make)
face-
factum
fact-
venire (to come)
veni-
ventum
vent-
audire (to hear)
audi-
auditum
audit-
    Deponent Verbs
    There is a class of Latin verbs called deponent —verbs that are conjugated with the passive endings only, but that have active meanings. The conjugation to which each deponent verb belongs is identified in the infinitive form already noted. The mark of the passive infinitive is a final -i .
     
The first conjugation deponent verb is distinguished by an a in the infinitive form:
    arbitror-arbitr a ri-arbitratum = think
    hortor-hort a ri-hortatum = urge
The second conjugation deponent verb is distinguished by an ē in the infinitive form:
    fateor-fatēri-fassum = speak
    mereor-mer ē ri-meritum = deserve
The third conjugation deponent verb loses the ēr in the infinitive and retains only the final i as the indication of the infinitive:
    sequor-sequ i -secutum = follow
    revertor-revert i -reversum = return
The fourth conjugation deponent verb is distinguished by an i in the infinitive form:
    experior-experir i -expertum = try
Examples
     
Present Infinitive
Present Stem
Perfect Participle
Perfect Stem
arbitrari (to think)
arbitra-
arbitratum
arbitrat-
hortari (to urge)
horta-
hortatum
hortat-
fatēri (to speak)
fatē-
fassum
fass-
merēri (to deserve)
merē-
meritum
merit-
sequi (to follow)
seque- 6
secutum
secut-
reverti (to return)
reverte-
reversum
revers-
experiri (to try, attempt)
experi-
expertum
expert-
    As we shall see, there are many English words that are derived from these verbs.
    SOME VERY USEFUL LATIN VERBS
     
Principal Parts
English Meaning
Present Stem
Perfect Stem
ago-agere-actum
do,