在三重语言市场中，内部和本地语言市场扩张同外部语言市场反蚀形成的双重运动是语言多样性式微的机制。现代社会不断增强的流动性和开放性提供了内部语言市场和本地语言市场弱扩散的机会，同时也使外部语言市场迅速蚕蚀内部和本地语言市场。其中，三大机制形塑了这一双重运动的过程及其结果，分别是作为经济机制的生计模式、作为社会机制的语言功能和作为权力机制的语言政策。随着人的生计模式由传统转向现代，语言功能从以生活需求满足为主转向生活、生产和发展需求满足并重，旨在统一语言以降低全社会交易成本的语言政策赋予了外部语言市场的强反蚀能力。而弱扩散和强反蚀相互作用的结果是内部和本地语言市场逐渐被稀释。京族聚居区语言变迁的典型个案说明了三重语言市场在民族地区语言变迁现象中的解释力和应用价值。在民族地区迈向共同富裕的社会景观和统一语言市场的进程中，需要更多创新的政策工具和社会行动来维系多样化的语言景观。

三重语言市场, 语言竞争, 语言功能, 语言政策, 双重运动, 语言变迁

In triplex language market, the social mechanism of the withering of language diversity is a double movement that generated from the expansion of internal and local language market and the erosion of external language market. The constantly increasing fluidity and openness in modern society have provided opportunities of minor diffusion for both internal and local language market, which meanwhile facilitates the external language market’ rapid invasion into the internal and local. Three mechanisms have shaped the process and brought out the results of this double movement, the model of livelihood as an economic mechanism, the linguistic function as a social mechanism, and the language policy as a power mechanism, respectively. The function of language transformed from mainly meeting living demands to satisfying the needs of life, production and individual development equally, along with the livelihood model of people transformed from traditional to modern, policies of the unification of language were devised to lower the transaction cost of the society, which have vested the power of market erosion in external language. The interaction of minor diffusion and strong erosion brought about the progressive dilution of internal and local language market.

triplex language market, competition of language, language function, language policy, double movements, transition of language