Non-English literature: should we check for prior work? How far should we go when considering the possibility that a (non spectacular, bur relevant) result has already appeared in any other language different from English?

Is it safe to ignore non-English publications in some fields like computer science, chemistry or physics? That would be assuming that foreign researchers will publish in English, if they are serious about it.
Is it safe to ignore non-English publications in some fields like computer science, chemistry or physics? 


I would try my best to not ignore. If you are citing a paper that has cited a non english journal, I would read the citation to see if its relevant to my paper. Translation tools, although not always accurate, would give you a sense what the paper is talking about. 
Maybe this article can answer your question to an extent. 

http://www.ete-online.com/content/5/1/12