Set the visitor UI language automatically

It's a little harder to implement automatically, but you could probably more easily do a dropdown that sets a registered user's preference, but to persist an anonymous user's preferences, you'd have to get Khoros support to turn on 

enable.PersistentAnonymousUserSettings = true

in your config.js file.  

If you want to get a parameter from the url, since your CDN/rp rewrites everything, you can use

https://developer.khoros.com/khoroscommunitydevdocs/reference/url

 to get the url and use the freemarker ?index_of to find what you're looking for in the string,

https://freemarker.apache.org/docs/ref_builtins_string.html#ref_builtin_index_of 

for example, though a bit messy because it's in longhand, it'll work:

<#assign myUrl = "http://somewebsite.com/purple/my/lang/cues/en/hello-there"/>
<#assign myLangStart = myUrl?index_of("my/lang/cues/") />
<#assign myLangEnd = myLangStart+1 />
<#assign myLang = myUrl[myLangStart..myLangEnd] />


myUrl: ${myUrl}
myLangStart; ${myLangStart}
myLangEnd: ${myLangEnd}
myLang: ${myLang}

And then set the language via modifying the user setting through the API. I'll find the link for you tomorrow.