Ok, there is also the idea of contractions. "don't", etc. another refinement...

m/(["'])(.+?)\1/;
[download]

If you tag the ["'], then using \1 looks for which ever quote character matched at the beginning. I think some \W also needed in some fashion. For a don't in the middle of a sentence. There may a special case when line beings with no character at all in front of the quote. Not sure what the requirements are when 'foo" is encountered or other non-standard english constructions.

m/\W(["'])(.+?)\1\W/;
[download]

Its tricky to think of all cases!