According to the usual modern analysis,
Early Middle Chinese had three
phonemic tones in most syllables, but no tonal distinctions in checked syllables ending in the
stop consonants /p/, /t/, /k/. In most circumstances, every syllable had its own tone; hence a multisyllabic word typically had a tone assigned to each syllable. (In modern varieties, the situation is sometimes more complicated. Although each syllable typically still has its own
underlying tone in most dialects, some syllables in the speech of some varieties may have their tone modified into other tones or neutralized entirely, by a process known as
tone sandhi. Furthermore, many
varieties of Chinese deleted Middle Chinese final consonants, but these contrasts may have
been preserved, helping lead to
tonogenesis of contemporary multitonal systems.) Traditional Chinese
dialectology reckons syllables ending in a stop consonant as possessing a fourth tone, known technically as a
checked tone. This tone is known in traditional Chinese linguistics as the
entering (
rù) tone, a term commonly used in English as well. The other three tones were termed the
level (or
even) tone (
píng), the
rising (
shǎng) tone, and the
departing (or
going) tone (
qù). From the perspective of modern
historical linguistics, there is often value in treating the entering tone as a tone regardless of its phonemic status, because syllables possessing this tone typically develop differently from syllables possessing any of the other three tones. For clarity, these four tones are often referred to as
tone classes, with each word belonging to one of the four tone classes. This reflects the fact that the lexical division of words into tone classes is based on tone, but not all tone classes necessarily have a distinct phonemic tone associated with them. Some contemporary
fāngyán such as
Taiwanese Hokkien,
Jin and
Penang are said to preserve the entering tone, which is used as a marker to differentiate them from other varieties and also genetically classify them via the
comparative method. The four Early Middle Chinese (EMC) tones are nearly always presented in the order
level (
píng),
rising (
shǎng),
departing (
qù),
entering (
rù), and correspondingly numbered 1 2 3 4 in modern discussions. In
Late Middle Chinese (LMC), each of the EMC tone classes split in two, depending on the nature of the initial consonant of the syllable in question. Discussions of LMC and the various modern varieties will often number these split tone classes from 1 through 8, keeping the same ordering as before. For example, LMC/modern tone classes 1 and 2 derive from EMC tone class 1; LMC/modern tone classes 3 and 4 derive from EMC tone class 2; etc. The odd-numbered tone classes 1 3 5 7 are termed
dark (
yīn), whereas the even-numbered tone classes 2 4 6 8 are termed
light (
yáng). Hence, for example, LMC/modern tone class 5 is known in Chinese as the
yīn qù (dark departing) tone, indicating that it is the
yīn variant of the EMC
qù tone (EMC tone 3). In order to clarify the relationship between the EMC and LMC tone classes, some authors notate the LMC tone classes as 1a 1b 2a 2b 3a 3b 4a 4b in place of 1 2 3 4 5 6 7 8, where
a and
b correspond directly to Chinese
yīn and
yáng, respectively.
Baxter's transcription, an alphabetic notation for representing Middle Chinese, represents the
rising (
shǎng) tone with a trailing
X, the
departing (
qù) tone with a trailing
H, and it leaves the level and entering tones unmarked. ==Names==