As a linguist, he acknowledges that all varieties of human language, including non-standard ones like Black English, can be powerfully expressive -- there exists no language or dialect in the world that cannot convey complex ideas.

　　① Illustrated with an entertaining array of examples from both high and low culture, the trend that Mr. McWhorter documents is unmistakable.

　　② But it is less clear, to take the question of his subtitle, why we should, like, care.

　　③ As a linguist, he acknowledges that all varieties of human language, including non-standard ones like Black English, can be powerfully expressive -- there exists no language or dialect in the world that cannot convey complex ideas.

　　④ He is not arguing, as many do, that we can no longer think straight because we do not talk proper.

　　参考译文：

　　①(观点：分1)麦荷特先生从上层和下层中列举了一系列有趣的例子，从而说明他所记录的这种趋势是确凿无误的。

　　②(转折：分2)但就书中副标题中的疑问：为什么我们应该喜欢或在意，答案却不够明确。

　　③(观点：总1)作为语言学家，麦荷特认为各种各样的人类语言，包括像黑人英语这样的非标准语言，都具有强大的表达力——世上没有传达不了复杂思想的语言或方言。

　　④(并列：总2)不像其他大多数人，麦荷特先生并不认为我们说话方式不再规范就会使我们不能够准确地思考。