Humanities › History & Culture How to Conjugate the Irregular Latin Verb Sum "To Be" The Proper Conjugations of Esse Share Flipboard Email Print "I am a Roman citizen." A proud graffito on via dell'Umiltà. CC BY 2.0 by antmoose History & Culture Ancient History & Culture Ancient Languages Basics Major Figures & Events Greece & Sparta Egypt Asia Rome Literature Mythology & Religion American History African American History African History Asian History European History Family History & Genealogy Inventions Latin American History Medieval & Renaissance History Military History The 20th Century Women's History View More by N.S. Gill N.S. Gill is a freelance classics and ancient history writer. She has a master's degree in linguistics and is a former Latin teacher. Updated September 05, 2018 The Latin word sum is perhaps among the best known of all the Latin verbs and it is among the hardest to learn. Sum is the present indicative tense of the verb esse, meaning "to be." As with many other living and dead languages, esse is one of the oldest verb forms in Latin, one of the most frequently used of the verbs, one of the most irregular verbs in Latin and related languages. It is also often contracted in casual use (such as in English I'm, that's, they're, he's), becoming almost invisible to the listener. Etymology The progenitor form of "to be" is in the Proto-Indo-European (PIE) language, the parent language of Latin, Greek, Sanskrit, Iranian, Germanic, and indeed most of the languages spoken in all of Europe, India, and Iran. Each of the PIE languages has a form of "to be," perhaps because it is so eminently useful: sometimes "to be" can have an existential significance ("To be or not to be, I think therefore I am"), but also retains its use in everyday language. In etymological circles, to be is the b-root word, and like all of the b-roots probably is derived from an ancient PIE root, today reconstructed as *h1és-mi (I am). It is also possible that "to be" in Latin derives from the root word *bhuH- meaning "to grow." Other closely related words to esse are asmi in Sanskrit and ešmi in Hittite. Conguating Sum Mood Tense Person Singular Plural indicative Present First sum sumus Second es estis Third est sunt Imperfect First eram eramus Second eras eratis Third erat erant Future First ero erimus Second eris eritis Third erit erunt Perfect First fui fuimus Second fuisti fuistis Third fuit fuerunt Pluperfect First fueram fueramus Second fueras fueratis Third fuera fuerant Future Perfect First fuero fuerimu Second fueris fueritis Third fuerit fuerint Subjunctive Present First sim simus Second sit sitis Third sit sint Imperfect First essem essemus Second esses essetis Third esset essent Perfect First fuerim fuerimus Second fueris fueritis Third fuerit fuerint Pluperfect First fuissem fuissemus Second fuisses fuissetis Third fuisset fuissent Irregular Verbs and Compounds There are several other Latin irregular verbs and compound verbs formed from sum. Eo - to go Fio - to become nolo, nolle, nolui - 'to be unwilling' and malo, malle, malui 'to prefer' are similar. Volo - to wish Fero - to carry Sum - to becompounds: adsum, desum, insum, intersum, praesum, obsum, prosum, subsum, supersum Do - to give Edo - to eat Continue Reading Moods of Latin Verbs: Indicative, Imperative and Subjunctive How to Conjugate the Irregular French Verb 'Boire' How Are Latin Infinitives Formed? A List of the Principal Parts of Irregular Verbs in English: H-S Paradigm for the Latin Irregular Verb EO Latin Verbs - Deponents Nolo (Irregular Latin Verb) Definition and Use What Do the Latin Verb Tenses Mean? All About 'Dormir,' an Irregular French Verb Like 'Partir,' 'Sortir' The Irregular French Verb 'Apprendre' ('to Learn') How to Conjugate Regular 3rd Conjugation Latin Verbs Where's the Action in Latin Verbs? It's All in the Details What Are Irregular Verbs in English? Conjugating the Irregular French Verb 'Devenir' (to Become) How Do You Conjugate the Irregular French Verb "Haïr"? How to Conjugate the Irregular French '-ir' Verb 'Offir'