[development] Max size of $language->language property

So for Activity module we provided multilingual messages not by using t() or tt() but by simply providing a messages per enabled language and for the language column we use $language->language which is 'en', 'en-us'. See this issue: http://drupal.org/node/634006 It appears that is done wrong though, http://drupal.org/node/651174, as this user claims that $language->language = "zh-hans". So what is the right way to handle $language in database tables? What part of the $language object to you use as the field and how large should the column be? And where does it belong on this handbook: http://drupal.org/contributors-guide -- Scott Reynolds