On tone genesis in Vietnamese

Even though there is a fairly well accepted model for the development of tones in Vietnamese, linguists still have questions about Vietnamese tonogenesis. One of the major remaining problems is the question of whether Vietnamese tones derive from Chinese tones or whether they developed independently. Scholars have traditionally argued that Vietnamese tones were borrowed from Chinese, and the parallels between Vietnamese and Chinese tones do support this idea. Yet evidence from the phonation features of tones also indicates that Vietnamese tonogenesis may have started before Chinese contact. These two conflicting views are both supported by strong linguistic evidence, making it difficult to definitively determine the source of Vietnamese tones.

Many point to the similarities between the tonal systems of Vietnamese and Middle Chinese (the older form of Chinese lasting from about the 5^th to 12^th centuries) as evidence that Vietnamese tones arose due to Chinese influence. In particular, Vietnamese tones seem to have developed in two splits (cf. Alves 1995). First, the loss of some final consonants and voice qualities created two non-level tones, resulting in three tone categories. A later split, based on whether initial consonants were voiced or voiceless, divided these three tone categories into the current six tones of Vietnamese (Thurgood 355).

By examining loan words and other sources, linguists have found parallels between the three original Vietnamese tone categories and Middle Chinese tones, particularly when it comes to the non-level tones. Vietnamese’s hoi and nga tones correspond to Middle Chinese’s departing tone, as all three tones
correspond to a /s/ in the earlier forms of their respective languages (Tsu-lin 87). Meanwhile, the rising tone in Middle Chinese matches the sac and nang tones of Vietnamese; these tones come from dropping a final glottal stop (Tsu-lin 88). These similarities seem to be more than just coincidences. For instance, the earliest Chinese loan words in Vietnamese almost always match their Chinese counterparts in tone (Pulleyblank 74). This observation leads many scholars to argue that language contact played an important role in the development of tonal systems. If language contact played an important role in tonogenesis, then a natural next step is to determine how tones moved between languages. Linguists usually say that tones originated in Chinese and spread to Vietnamese and other languages. After all, Chinese has played a more dominant role in the region. Vietnamese borrowed several loan words from Chinese, and Chinese even served as Vietnam’s literary language (Pulleyblank 69).

But there is another argument that suggests tones spread from Chinese to Vietnamese: as Pulleyblank argues, tones seem to have developed first in northern China. For instance, Buddhist transcriptions dating from the 2^nd century AD from northern China still use a final /s/; as discussed earlier, this final /s/ was dropped, leaving the departing tone in Middle Chinese. Northern Chinese transcriptions from the 4^th century do not use a final /s/, indicating the shift to tones had occurred already. But southern Chinese transcriptions retain the final /s/ until the 6^th century. Tones therefore developed first in northern China and subsequently spread south. By extension, if tones moved across languages, it is more likely that they spread south from China to Vietnam than in the opposite direction (76). In summary, the similarities between Vietnamese and Middle Chinese tones have convinced many linguists that tones spread between languages. And given the relation between Vietnamese and Chinese as well as the spread of tones within China, it would seem likely that Vietnamese tones arose due to Chinese influence.

But the complexity of Vietnamese tones has led some linguists to argue that Vietnamese tones arose independently of Chinese. While Vietnamese tones do match Chinese tones in pitch contour and height, they also have their own unique phonation features. These phonation features are often linked to the way the tones developed. For instance, the sac and nang tones often have a ‘creaky’ quality; more specifically, the vocal folds are tightly compressed for these tones, thereby producing a lower pitch and creating the ‘creaky’ quality. In fact, this ‘creaky’ quality derives from a special ‘creaky voice’ that existed in Proto-Vietic. In Vietnamese, words with this creaky voice developed into an almost separate tone category that merged with sac or nang tones (Thurgood 336). So the creaky voice played an active role in the development of tones. Just as nearby consonants create a vowel sound change that leads to some tones, the creaky voice contributed directly to tonogenesis. There are indications that the creaky voice dates back to Proto-Mon-Khmer. Both the Katuic and Pearic languages, which belong to the Mon-Khmer family, show evidence of a creaky voice. For instance, words with certain final consonants can have vowels with or without creakiness in the Katuic language Talan, indicating an earlier creaky voice (Diffloth 140). With evidence of the creaky voice in various Mon-Khmer languages, the creaky voice is likely a feature of Proto-Mon-Khmer (Diffloth 139). However, if the creaky voice was present in Proto-Mon-Khmer, then the creaky voice should have impacted Vietnamese prior to the spread of tonal systems through the region. In other words, the process that transformed the creaky voice into tones was already under way by the time tones supposedly spread from Chinese to Vietnamese (Alves 4). So a significant part of Vietnamese tonogenesis would have occurred prior to Chinese influence, suggesting that Vietnamese tones developed independently of Chinese.

Based on this discussion, the source of Vietnamese tones remains unclear. The Vietnamese tonal system does share many similarities with that of Middle Chinese, making it likely that language contact played an important role in tonogenesis. And if tones did spread between languages, the presence of Chinese loan-words in Vietnamese as well the development of tones within China indicate that Vietnamese borrowed tones from Chinese. At the same time, many of the features associated with Vietnamese tones, particularly the ‘creaky’ quality of the sac and nang tones, appear to have been present prior to Chinese contact. As a result, the process behind Vietnamese tonogenesis may have started without Chinese influence, which would make Vietnamese tones an independent innovation. Without further evidence, the question of whether Vietnamese tones came from Chinese or developed independently will likely stay unanswered.

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