Brivla are "content words", i.e., categorematic. When acting as selbri they are roughly comparable to verbs (or adjectives (or even nouns), if the selbri's arity is one), and when acting as sumti (e.g., due to being prefixed with "le") they are comparable to nouns. If a brivla modifies another one (thereby forming a "tanru"), the modifying brivla would be comparable to an adverb or adjective (*), depending on whether the modified brivla is acting as selbri or sumti, respectively. // Footnote: (*) - the modifying brivla could instead be comparable, in some cases, to the modified brivla's predicate.