Thus in the verb vocā-bā-s, you were calling, the root is VOC, modified into the verb-stem vocā-, which by the addition of the ending -bās becomes the imperfect tense vocābās; and this ending consists of the tense-sign bā- and the personal ending (-s) of the second person singular.
The tenses of the Present System are made from the Present Stem as follows:—
In the Present Indicative the personal endings are added directly to the present stem. Thus,—present stem arā-: arā-s, arā-mus, arā-tis.
In the Imperfect Indicative the suffix -bam, -bās, etc. (originally a complete verb) is added to the present stem: as, arā-bam, arā-bās, arā-bāmus.
In the Future Indicative of the First and Second Conjugations a similar suffix, -bō, -bis, etc., is added to the present stem: as, arā-bō, arā-bis, monē-bō.
In the Future Indicative of the Third and Fourth Conjugations the terminations -am, -ēs, etc. (as, teg-am, teg-ēs, audi-am, audi-ēs) are really subjunctive endings used in a future sense (see e). The vowel was originally long throughout. For shortening, see § 167.
In the Present Subjunctive the personal endings were added to a form of the present stem ending in ē- or ā-, which was shortened in certain forms (§ 167). Thus, ame-m, amē-s, tegā-mus, tega-nt.
In the Imperfect Subjunctive the suffix -rem, -rēs, etc. is added to the present stem: as, amā-rem, amā-rēs, monē-rem, tege-rem, audī-rem.
The verb sum, be, is both irregular and defective, having no gerund or supine, and no participle but the future.
Its conjugation is given at the outset, on account of its importance for the inflection of other verbs.
PRINCIPAL PARTS: Present Indicative sum, Present Infinitive esse, Perfect Indicative fuī, Future Participle futūrus.
PRESENT STEM es-
PERFECT STEM fu-
SUPINE STEM fut-
INDICATIVE
SUBJUNCTIVE
PRESENT
SING.
1. sum, I am
sim
2. ĕs, thou art (you are)
sīs
3. est, he (she, it) is
sit
PLUR.
1. sumus, we are
sīmus
2. estis, you are
sītis
3. sunt, they are
sint
IMPERFECT
SING.
1. eram, I was
essem
2. erās, you were
essēs
3. erat, he (she, it) was
esset
PLUR.
1. erāmus, we were
essēmus
2. erātis, you were
essētis
3. erant, they were
essent
FUTURE
SING.
1. erō, I shall be
2. eris, you will be
3. erit, he will be
PLUR.
1. erimus, we shall be
2. eritis, you will be
3. erunt, they will be
PERFECT
SING.
1. fuī, I was (have been)
fuerim
2. fuistī, you were
fueris
3. fuit, he was
fuerit
PLUR.
1. fuimus, we were
fuerimus
2. fuistis, you were
fueritis
3. fuērunt, fuēre, they were
fuerint
PLUPERFECT
SING.
1. fueram, I had been
fuissem
2. fuerās, you had been
fuissēs
3. fuerat, he had been
fuisset
PLUR.
1. fuerāmus, we had been
fuissēmus
2. fuerātis, you had been
fuissētis
3. fuerant, they had been
fuissent
FUTURE PERFECT
SING.
1. fuerō, I shall have been
PLUR.
1. fuerimus, we shall have been
2. fueris, you will have been
2. fueritis, you will have been
3. fuerit, he will have been
3. fuerint, they will have been
IMPERATIVE
PRESENT
SING.
2. ĕs, be thou
PLUR.
2. este, be ye
FUTURE
2. estō, thou shalt be
2. estōte, ye shall be
3. estō, he shall be
3. suntō, they shall be
INFINITIVE
PRESENT
esse, to be
PERFECT
fuisse, to have been
FUTURE
futūrus esse or fore, to be about to be
PARTICIPLE
FUTURE
futūrus, -a, -um, about to be
For essem, essēs, etc., forem, forēs, foret, forent, are often used; so fore for futūrus esse.
The Present Participle, which would regularly be †sōns,
appears in the adjective īn-sōns, innocent, and in a modified form in ab-sēns, prae-sēns. The simple form ēns is sometimes found in late or philosophical Latin as a participle or abstract noun, in the forms ēns, being;entia, things which are.
The root of the verb sum is ES, which in the imperfect is changed to ER (see § 15. 4), and in many forms is shortened to S. Some of its modifications, as found in several languages more or less closely related to Latin, may be seen in the following table,— the Sanskrit syām corresponding to the Latin sim (siem):—
SANSKRIT
GREEK
LATIN
LITHUANIAN
as-mi
syām (optative)
e)/mmi (old form)
s-um
sim (siem)
es-mi
as-i
syās
e)ssi/ (old form)
es
sīs (siēs)
es-i
as-ti
syāt
e)sti/
es-t
sit (siet)
es-ti
s-mas
syāma
e)sme/n
s-umus
sīmus
es-me
s-tha
syāta
e)ste/
es-tis
sītis
es-te
s-anti
syus
e)nti/ (old form)
s-unt
sint (sient)
es-ti
The Perfect and Supine stems, fu-, fut-, are kindred with the Greek e)/fu, and with Nhe English be.