Recitative can be distinguished on a continuum from more speech-like to more musically sung, with more sustained melodic lines. The mostly syllabic recitativo secco ("dry", accompanied only by continuo, typically cello and harpsichord) is at one end of the spectrum, through recitativo accompagnato (using orchestra), the more melismatic arioso, and finally the full-blown aria or ensemble, where the pulse is entirely governed by the music. Secco recitatives can be more improvisatory and free for the singer, since the accompaniment is so sparse; in contrast, when recitative is accompanied by orchestra, the singer must perform in a more structured way.
