Funny, I asked myself the same question a few days ago. For that you can look at the ids of the local section. 
For example :
Russian section: https://bitcointalk.org/index.php?board=10.0 (id: 10)
French section; https://bitcointalk.org/index.php?board=13.0 (id: 13)
Arabic section: https://bitcointalk.org/index.php?board=241.0 (id: 241)

It will give you an idea.