The Verb “Esse”

THE VERB TO BE

Although Latin does have four regular verb conjugations, some verbs simply do not conjugate quite like the others. These are usually called irregular verbs, and they are among some of the most frequently used of all Latin verbs.
One such verb is the verb “to be.” Its principal parts are given below:

sum, esse, fuī, futūrus

Recall that these principal parts are listed in the dictionary entries for all Latin verbs. Although all four of these look very different to each other, they all nonetheless come from the same verb!

To see how this verb looks in all its conjugated forms in the present, consult the table below:

Although esse does not seem to conjugate in the same way as most other verbs, there is in fact a recognizable pattern at work here! Apart from the first person singular sum, all the other forms of this verb have the same regular present tense endings you would expect from a verb like amāre. They are, as follows: 

2nd. person singular: -s

3rd. person singular: -t

1st. person plural: -mus

2nd. person plural: -tis 

3rd. person plural: -nt

Have you studied a Romance language like French, Italian, or Spanish? If you have, and think that some of the forms of the verb esse look familiar, your intuition is spot on! Perhaps somos in Spanish looks like sumus, while est in French and est in Latin look identical, and so on. All of these forms are direct descendants of the Latin original.

Latin frequently forms compounds with the verb esse and other prepositions and adjectives. The verb abesse, for instance, combines the preposition ab (away from) and esse, which conjugates exactly the same as esse: absum, abes, abest, and so on.
Another one of the most common irregular Latin verbs is posse (“to be able to”). This verb itself is a compound of the adjective potis, pote (“able to, capable of”) and esse. To conjugate this verb, add pos- to the forms of esse that start with s, and add pot- to the forms of esse that start with t. Consult the table below for the full conjugation of the verb in the present tense: