Using the wordpress editing, add a custom field called tp_language and insert the two letter code of the language used in that post, so if your blog is in English and you have a post in Spanish just add tp_language es as a custom field.
Kutumia editing WordPress, kuongeza shamba desturi aitwaye tp_language na kuingiza barua mbili kanuni za lugha ya kutumika katika post kwamba, hivyo kama blog yako ni katika Kiingereza na una post Kihispania tu kuongeza es tp_language kama shamba desturi.