This is not to say that English is used by a greater number of speakers than any other language: it is easily outnumbered in this respect with Chinese.

理解句义和结构经常需要上下文的。It 指代English。in this respect=在这一点上。与with没有直接关系。with Chinese是方式状语，修饰被动语态。你把 in this respect和with连起来去读，自然就无法理解了。要学会断句。