You can get the definition of this idiom here
you discuss prices on the high street
you talk about the news
you talk about work
talk shop is work related
I want to check the answer, but link doesn't work.
Last edited by bagzi94; 19-Mar-2011 at 07:59.
The link pointed to usingenglish's own idioms section, so you can look up the idiom there.
Bagzi94, I have just tested the link and it worked fine.
Probably someone replace it.