Part translation of concrete site

Hi all, what would be the best way to provide one part of a website translated but the main body of content in english?
For example you would land on the website, in english, then when you visit a sub section (say press releases), you’re then given the option to switch to another language. The press release titles would translate, but the main navigation/header and footer etc remains in english. When you open a press release. That is translated, but you can switch back to English if required.
Hopefully that makes sense.
Thanks in advance!

There are probably a few ways to do that. Do you have the translations already, or are you going to be using a service such as Google Translate?