Abstract: The combination rule of words in putonghua （standard colloquial Chinese） and its effect on the articulation score are discussed. It is shown that the articulation is dependant not only upon the external information of speech signal received by the listener, but also upon the internal information, the combination rule, of the language. And this effect is accounted for in a new formula expressing the relation between the articulation scores of different language units, which appears to be in better agreement with experimental results than those proposed by previous authors.