The monolingual children couldn 't answer .

单语儿童不会回答。

Bialystok is also studying physical differences between bilingual and monolingual brains .

比亚韦斯托克也正在研究双语者和单语者大脑之间的肉体差异。

In fact , monolingual countries are hard to find .

实际上，只使用一种语言的国家很难找到。

They came from monolingual and bilingual families , although the study did not specify which languages the families spoke .

这些宝宝有的来自双语家庭，有的来自单语家庭，虽然实验并没有关注各家庭所说的是哪种语言。

By 10 to 12 months , however , monolingual babies were no longer detecting sounds in the second language , only in the language they usually heard .

然而，到10至12个月时，单语婴孩便不再能感知第二种语言的声音，只能发觉他们过去听到过的语种。