单选题 ______ is the study of the characteristics of language varieties, the characteristics of their functions and the characteristics of their speakers as these three constantly interact and change within a speech community.
【正确答案】 B
【答案解析】[解析] 社会语言学研究的是语言变体的特征、它们的功能特征、讲话者的特征以及这三者如何在言语团体中持续地相互作用和变化。
本题考查常识。psycholinguistics语言心理学；sociolinguistics社会语言学；anthropological linguistics人类语言学；computational linguistics计算机语言学。故选B。