This site below has got a very strong seo presence. And I see it uses language=en and region=gb in the url.
http://www.accuweather.com/en/gb/united-kingdom-weather
I was looking into this but couldn't find any article/documentation.. Thanks in advance, if you read this question and gave a thought on this.
The only thing that the URL makes a difference for is that Google considers two pages with different URL paths as different pages. Having /en/gb in the URL won't make it any easier or worse for Google. Google may see these clues and index the pages appropriately with those clues but that is not a promise. More often than not URL hints will be ignored, or rather ranked as a lower signal than the page content itself.
The thing you could encounter is if you have various pages that are substantially the same and have substantially the same content (such as being the same and the only difference being a few words related to local language differences). In this case you may wind up with a duplicate content penalty. The URL parameters you are using are of more use to end users however even then many end users won't care about the URL path and will want to see that sort of information on the page itself.
For example with many of the multi-region multi-language sites I manage I place a geographic selector in the header of the page to let the user choose between for instance the US site, Australian site, or Great Britan site. I also embed a translator widget in so that if the user wants to read the content in another language they can select their language and they will be redirected to the translated page. The key here is that this data doesn't get embeded within the URL of the site, rather I use headers, meta data, and cookies to identify that data.
