I’m trying to say that the linguists were “astounded at his progress”:
The eminent linguists who were teaching him were staggered by his
remarkable progress. They were the ones learning from him before long,
so it was only natural.
Also, should it be “staggered by” or “staggered at”?
The usage is correct (definition 2a: to overwhelm with emotion or astonishment), and both staggered by and staggered at seem to be correct.
Source : Link , Question Author : Soulz , Answer Author : Renan