Best practice for URLs of multi-language websites

Question

What is considered the best strategy for URLs of translated websites? Something I see happen frequently is:

http://example.com/english-slug.html
http://examp         


        

Answer 1

Another way is setting the language as a query string parameter, such as:

http://example.com/hello-world?hl=en

http://example.com/hallo-welt?hl=de

for example Google Flights web site uses this method.