Query: What word supplement  can be put on an already existing word base?
Context: The process of morphological derivation in Catalan follows the same principles as the other Romance languages, where agglutination is common. Many times, several affixes are appended to a preexisting lexeme, and some sound alternations can occur, for example elèctric [əˈlɛktrik] ("electrical") vs. electricitat [ələktrisiˈtat]. Prefixes are usually appended to verbs, for as in preveure ("foresee").