The Irregular Verb Sum and Its Compounds

These verbs are all compounds of the irregular verb "to be," (sum, esse, fui, futurus) and will frequently take the dative case. Verba mihi desunt, for instance, is the way a Roman would say "words fail me," or "I'm speechless." See Gildersleeve & Lodge: 347, Dative and Verbs Compounded with Prepositions, for more examples.