Abstract : This study examines a corpus of 300 compositional phrasal verbs in English using the particle up. Whereas frozen phrasal verbs clearly do not have the same meaning without the particle and must be listed in the lexicon grammar of idiomatic expressions (e.g., break up the audience “cause to laugh”), compositional phrasal verbs merely add an aspectual element to the simple verb, and particle usage might be better analyzed as a property of the simple verb. Although this meaning is difficult to characterize precisely, it generally indicates direction (ride up the elevator), completion (open up the store), intensity (hype up the book), or combinations (polish up the silverware, completion and intensity). These properties are added to the table of compositional phrasal verbs. Optional particle usage can also identify the meaning of a potentially ambiguous simple verb. For example, the simple verb call “phone” can take the particle up but not out, while the simple verb call “announce” can take the particle out but not up. The simple verb tables, however, will become enormously complex when all English particles (fifteen different particles according to B. Fraser 1976) are taken into account.