All forms of verbs, verbal nouns, and verbal adjectives are formed by the addition of specific endings to verbal stems derived from one of the four principal parts of a verb. Verbs are listed in dictionaries by their 1st principal part and the final three letters of their 2nd principal part (e.g. amo, -are). The 3rd and 4th principle parts of verbs will only be listed if they are irregular, otherwise, form them as indicated below.
In combination with the 2nd principal part, the 1st indicates to which of the four conjugations a verb belongs.
1st conjugation: -o, -are , -avi, -atum
2nd conjugation: -eo, -ere, -ui, itum
3rd conjugation: -o, -ere, -???, -???
4th conjugation: -io, -ire, -ivi, -itum
Nota bene: the ere of the 3rd is short in contrast to the ere of the 2nd conjugation; in addition, the 3rd and 4th principal parts of 3rd conjugation verbs typically differ in spelling from the 1st and 2nd principal parts, frequently having either [-s-] or [-x-]. e.g. pono, ponere, posui, positum; duco, ducere, duxi, ductum)
1. [Ama-tur] PRESENT ACTIVE and PASSIVE INDICATIVE verbs are formed by adding the present active (-o, -s, -t; -mus, -tis, -nt) or passive (-r, -ris, -tur; -mur, -mini, -ntur) endings to the present stem. [he is loved]
2. [Am-e-tur] PRESENT ACTIVE and PASSIVE SUBJUNCTIVE verbs are formed by adding the present active and passive endings to the stem after its characteristic stem vowel has been shifted: sic 1st ama- --> am-e-; 2nd habe- --> habe-a-; 3rd legi- --> leg-a-; 4th dormi- --> dormi-a-. [context determines subjunctive translation]
3. [Ama-ba-tur] IMPERFECT ACTIVE and PASSIVE INDICATIVE verbs are formed by adding (-ba-) to the present stem and then the present active (1st person singular is -m) or passive endings. [he was being loved]
4. [Ama-re-tur] IMPERFECT ACTIVE and PASSIVE SUBJUNCTIVE verbs are formed by adding the present active or passive endings to the present active infinitive.
5. [Ama-bi-tur] FUTURE ACTIVE and PASSIVE INDICATIVE verbs are formed for the 1st and 2nd conjugations by adding (-bo, -bi-, -bi-; -bi-, -bi-, -bu-) and then the present active or passive endings to the stem. Verbs of the 3rd and 4th conjugation are formed by adding (-a-, -e-, -e-; -e-, -e-, -e-) and then the present active (1st person singular is -m) or passive endings to the stem. The stem of the 3rd contains no stem characteristic vowel (e.g. lego, legere --> leg-e-t), whereas the 4th retains its stem characteristic i- (e.g. dormio, dormire --> dormi-e-t). The 2nd person singular passive substitutes be- for -bi-; e.g. ama-be-ris. [he will be loved]
6. [Ama-ri] PRESENT PASSIVE INFINITIVE (verbal noun) are formed by adding (-ri) to the present stem. 3rd conjugation verbs substitute an (-i) for (-ri): sic ducere (active), duci (passive). [to be loved]
7. [Ama] PRESENT ACTIVE IMPERATIVE verbs the present stem is used for the singular, plurals are formed by adding (-te) to the present stem. (3rd conjugation shifts its stem vowel to [i-] in the plural thus: singular pone, but plural poni-te) [love!]
8. [Ama-to] FUTURE ACTIVE IMPERATIVE verbs are formed in the singular by adding (-to) to the present stem, and in the plural by adding (-tote) to the present stem. [go on and love!]
9. [Ama-nt-em] PRESENT ACTIVE PARTICIPLES (verbal adjectives) are formed by adding (ns, -nt-is) to the present stem as with 3rd declension "i-stem" adjectives (e.g. ama-ns, ama-nt-em, ama-nt-is, etc.). The ablative singular is (i) for adjectival and (-e) for verbal and ablative absolute usage. [loving]
10. [Ama-nd-um] GERUNDS (verbal nouns) are formed by adding (nd-) and (-um, -i, -o, -o) to the present stem. All gerunds are neuter and singular; no nominative exists. [loving]
11. [Ama-nd-us] GERUNDIVES (verbal adjectives) are formed by adding (nd-) and 1st and 2nd declension case endings to the present stem. [about to be loved; needing to be loved]
12. [Ama-nd-us est] Passive Periphrastic Conjugation is formed by the pairing of the gerundive with a form of esse. The tense of the periphrastic is the same as the form of [esse] used. [he is needing to be loved; he needs to be loved; he must be loved.]
1. [Amav-it] PERFECT ACTIVE INDICATIVE verbs are formed by the addition of the perfect active endings (-i, -isti, -it; -imus, -istis, -erunt) to the perfect stem. [he loved; he did love; he has loved]
2. [Amav-erit] PERFECT ACTIVE SUBJUNCTIVE verbs are formed by the addition of the future forms of esse ([erim], eris, erit; erimus, eritis, [erint]) to the perfect stem. Bracketed forms differ from the future of esse in spelling. Nota bene: the future of esse has no long [i-] when not combined with the perfect stem.
or [Amav-erit] FUTURE-PERFECT ACTIVE INDICATIVE verbs are formed by the addition of the future forms of esse (ero, eris, erit; erimus, eritis, [erint]) to the perfect stem. Bracketed form differs from the future of esse. Nota bene: the perfect active subjunctive and the future-perfect active indicative differ morphologically only in the 1st person singular and in the presence of the (-i-). [he shall have loved]
3. [Amav-isse] PERFECT ACTIVE INFINITIVES (verbal nouns) are formed by the addition of (-isse-) to the perfect stem. [to have loved]
4. [Amav-erat] PLUPERFECT ACTIVE INDICATIVE verbs are formed by the addition of the imperfect forms of esse (-eram, -eras, -erat; -eramus, -eratis, -erant) to the perfect stem. [he had loved]
5. [Amav-isse-t] PLUPERFECT ACTIVE SUBJUNCTIVE verbs are formed by the addition of the present active endings (1st person singular is -m) to the perfect infinitive.
1. [Amat-us] PERFECT PASSIVE PARTICIPLES (verbal adjectives) are formed by adding 1st and 2nd declension case endings to the perfect passive participle stem. [having been loved]
2. [Amat-um esse] PERFECT PASSIVE INFINITIVES (verbal nouns) are formed by the pairing of an accusative (in indirect speech) or nominative (as substantival) form of the perf. pass. part. with esse. [to have been loved]
3. [Amat-us est] PERFECT PASSIVE INDICATIVE verbs are formed by the pairing of perfect passive participle with the present indicative forms of esse (sum, es, est; sumus, estis, sunt). [he was loved]
4. [Amat-us sit] PERFECT PASSIVE SUBJUNCTIVE verbs are formed by the pairing of perfect passive participle with the present subjunctive forms of esse (sim, sis, sit, simus, sitis, sint).
5. [Amat-us erat] PLUPERFECT PASSIVE INDICATIVE verbs are formed by the pairing of perfect passive participle with the imperfect indicative forms of esse (eram, eras, erat, eramus, eratis, erant). [he had been loved]
6. [Amat-us esse-t] PLUPERFECT PASSIVE SUBJUNCTIVE verbs are formed by the pairing of perfect passive participle with the imperfect subjunctive forms of esse (essem, esses, esset; essemus, essetis, essent).
7. [Amat-us erit] FUTURE-PERFECT PASSIVE INDICATIVE verbs are formed by the pairing of the perfect passive participle with the future forms of esse (ero, eris, erit; erimus, eritis, erunt). [he shall have been loved]
8. [Amat-ur-us] FUTURE ACTIVE PARTICIPLES (verbal adjectives) are formed by adding (-ur-) and 1st and 2nd declension case endings to the perfect passive participle stem. [he is about to love; he is going to love]
9. [Amat-u] SUPINES (verbal nouns) are formed by adding (-um or -u) to the perfect passive participle stem. [amatum = for the purpose of loving; in order to love: amatu = with respect to loving; in loving; to love]
10. [Amat-ur-us est] Active Periphrastic Conjugation: is formed by the addition of a form of esse to the future active participle. This form is can be used as a periphrasis for the future, including in the subjunctive. The tense of the periphrastic is the same as the form of [esse] used. [He is about to love, he is going to love He will love.]
11. [Amat-ur-um esse] FUTURE ACTIVE INFINITIVES (verbal nouns) are formed by the pairing of the accusative form of the future active participle with esse. [to be about to love, to be going to love]
12. [Amat-um iri] FUTURE PASSIVE INFINITIVES (verbal nouns) are formed by the pairing of the accusative form of the supine with iri. This form is quite rare. [to go for the purpose of loving; to be about to be loved]