From the Latin suppletivus and the verb suppleo , complete, add, suplir . Relating to substitution, replacement, replacement or exchange. It is usually said, for example, of verbs that have several lexical roots, such as the verb to be or the verb to go. The irregularity of our verb ir alternates radicals from the Latin verbs ire ( iba ) , vadere ( voy ) and esse ( fui ) .