VOA慢速英语:Somewhere a Language Dies Every Two Weeks

in danger of有…的危险

例句：This kind of animal is in danger of becoming extinct.
      这种动物有灭绝的危险。

2.Their ancient languages contain a great deal of information about environmental systems and species of plants and animals that are unknown to scientists.

a great deal of很多的

例句：Some animals have a great deal of cunning.
      一些动物很狡猾。

      She assembled a great deal of information for the report.
      她为写这篇报告收集了大量资料。

3.Why is it a secret language? Kallawaya is passed down within families from father to son as a way of protecting the special knowledge of healers.

pass down把…一代传一代; 使流传
 
例句：This custom has been passed down since the 18th century.
       这个风俗从18世纪就沿袭下来。