I have modified the code a bit , to tackle that english error to (check screen shot) 
and  You are talking about to wrap 'Delete %(lang_code)s' in a call to gettext ,  is it ok ?

if ( lang_code != 'en')
	    lang_description += sprintf("<div class='delete-language-button'> <button value='%s' type='button'>%s</button></div>", lang_code, sprintf(gettext('Delete %(lang_code)s'), {lang_code: lang_code}));

I am asking all the question here , so to prevent any extra PR. 

![third](https://f.cloud.github.com/assets/4207886/2386767/b74330a8-a92f-11e3-9b7e-39d0b039c823.png)