Can't choose a language with API v3 in multilingual sites

I want for example to get list of options values in a specific language but i can't find a way to specify the language. I get only label of language default when doing :
$results=civicrm_api("OptionValue","get", array (version => '3','sequential' =>'1');

I tried to set $tsLocale before but it doesn't seems to work neither :
global $tsLocale;
$tsLocale = 'fr_CA';
$results=civicrm_api("OptionValue","get", array (version => '3','sequential' =>'1');

So i'd like to either be able to specify a language like 'locale' => 'fr_CA' or have all the variant in the result : label_fr_CA, label_en_CA instead of label.