可能在人口流动性方面最具说服力的标志是，公元前3000年，在这片广袤的土地上大部分牧民讲的相关语言，现代印欧语系就从中发展而来。

Perhaps the most striking sign of mobility is the fact that by the third millennium B.C., most pastoralists in this huge region spoke related languages ancestral to the modern Indo-European languages.

youdao

我们的人口流动性很大。

We have a very transient population here.

youdao

美国人口流动性很高，有能耐的人会迁移向其他所得税低的州。

Americans are highly mobile, so the most able will simply leave for another state.

youdao