“Fifth tone” is a term that has been employed in characterizations of Mandarin phonology with several different meanings. It is most commonly used to refer to the so-called neutral tone or light tone (qīngshēng 輕聲). This term is employed in analyses that view the unstressed, short tone found in a small number of grammatical particles (e.g., the subordinating particle de [tə] 的) as a phonemic lexical tone distinct from the four basic tones of modern standard Mandarin. It is also often employed in informal descriptions of the standard Mandarin tone system…