Even in a conventional Western piece of instrumental music, in which all of the melodies, chords, and basslines are written out in musical notation, the performer has a degree of latitude to add artistic interpretation to the work, by such means as by varying his or her articulation and phrasing, choosing how long to make fermatas (held notes) or pauses, and — in the case of bowed string instruments, woodwinds or brass instruments — deciding whether to use expressive effects such as vibrato or portamento. For a singer or instrumental performer, the process of deciding how to perform music that has been previously composed and notated is termed “interpretation”. Different performers’ interpretations of the same work of music can vary widely, in terms of the tempos that are chosen and the playing or singing style or phrasing of the melodies. Composers and songwriters who present their own music are interpreting, just as much as those who perform the music of others. The standard body of choices and techniques present at a given time and a given place is referred to as performance practice, whereas interpretation is generally used to mean the individual choices of a performer.