Sino-Vietnamese vocabulary (, Chữ Hán: 詞漢越, literally 'Chinese-Vietnamese words') is a layer of some 3,000 monosyllabic morphemes of the Vietnamese language borrowed from Literary Chinese with consistent pronunciations based on "Annamese" Middle Chinese. Compounds using these morphemes are used extensively in cultural and technical vocabulary. Together with Sino-Korean and Sino-Japanese vocabularies, Sino-Vietnamese has been used in the reconstruction of the sound categories of Middle Chinese. Samuel Martin grouped the three together as "Sino-xenic". There is also an Old Sino-Vietnamese layer consisting of a few hundred words borrowed individually from Chinese in earlier periods. These words are treated by speakers as native. More recent loans from southern varieties of Chinese, usually names of foodstuffs such as 'Chinese sausage', are not treated as Sino-Vietnamese. Estimates of the proportion of words of Chinese origin in the Vietnamese lexicon vary from one third to half and even to 70%. The proportion tends towards the lower end in speech and towards the higher end in technical writing. In the famous dictionary by Vietnamese linguist , about 40% percent of vocabulary are of Chinese origin. Monosyllabic loanwords As a result of a thousand years of Chinese control (except for brief rebellions), and a further thousand years of use of Literary Chinese after independence, two main layers of Chinese vocabulary have been borrowed into Vietnamese. These layers were first systematically studied by linguist Wang Li. Middle Chinese and Vietnamese, like most languages of the Mainland Southeast Asia linguistic area, are analytic languages. Almost all morphemes are monosyllabic and lacking inflection. The phonological structure of their syllables is also similar. The Old Sino-Vietnamese layer was introduced after the Chinese conquest of the kingdom of Nanyue, including the northern part of Vietnam, in 111 BC. The influence of the Chinese language was particularly felt during the Eastern Han period (25–190 AD), due to increased Chinese immigration and official efforts to sinicize the territory. This layer consists of roughly 400 words, which have been fully assimilated and are treated by Vietnamese speakers as native words. The much more extensive Sino-Vietnamese proper was introduced with Chinese rhyme dictionaries such as the Qieyun in the late Tang dynasty (618–907). Vietnamese scholars used a systematic rendering of Middle Chinese within the phonology of Vietnamese to derive consistent pronunciations for the entire Chinese lexicon. After driving out the Chinese in 880, the Vietnamese sought to build a state on the Chinese model, including using