Irregular Verbs: “esse” and “posse”

Present SystemMagister Henderson

Latin II

About “sum, esse” (to be)• The verb sum, esse is a linking verb, meaning

it takes a predicate nominative rather than a direct object.

• It is irregular in all three forms of the present system (present, imperfect, and future).

Present Tense Singular Plural

First Person sum = I am sumus = we are

Second Person es = you are estis = you are

Third Person est = he / she / it is sunt = they are

Imperfect and Future of “esse”

Imperfect Tense Singular Plural

First Person eram = I was erāmus = we were

Second Person erās = you were erātis = you were

Third Person erat = he / she/ it was erant = they were

Future Tense Singular Plural

First Person erō = I will be erimus = we will be

Second Person eris = you will be eritis = you will be

Third Person erit = he will be erunt = they will be

About “possum, posse” (to be able)

• Compound form of potis and sum, esse.• The prefix “pot-” is used for forms of esse that

begin with “s” (sum, sumus, and sunt).• For forms that begin with “e” (es, est, and

estis), the prefix assimilates to “pos-”.

Present Tense Singular Plural

First Person possum = I can possumus = we can

Second Person potes = you can potestis = you can

Third Person potest = he / she / it can possunt = they can

Imperfect and Future of “posse”

Imperfect Tense Singular Plural

First Person poteram = I could poterāmus = we could

Second Person poterās = you could poterātis = you could

Third Person poterat = he / she / it could poterant = they could

Future Tense Singular Plural

First Person poterō = I will be able potermus = we will be able

Second Person poteris = you will be able poteritis = you will be able

Third Person poterit = he will be able poterunt = they will be able

All the imperfect and future tense forms of posse use “pot-” since all forms of esse in the imperfect and future tenses begin with the letter “e”.

Translating the verb “posse”• To translate possum, posse use either the defect

verb “can” or the phrase “be able (to)”.• Defective verbs are verbs that are missing forms.

For the missing forms you will need to use some form of “be able (to)”.

Form Latin Verb Translation Phrase Translation

Infinitive posse n/a = to be able (to)

Present tense possum = I can = I am able (to)

Imperfect Tense poteram = I could = I was able (to)

Future Tense poterō n/a = I will be able (to)