php single table language separated autoincrements?
It sounds like you're saying you have the same posts available in different languages. Assuming that's the case, I'd split the table in two.

post would have the basic info about the post that is not language dependent:


the unique ID for that post's content
the ID of the user who wrote the post
the date the post was created
...


post_language would be the content for each specific post, translated into a specific language:


post_lang_id - unique ID for this post_language row
post_id - foreign key to post; identifies the underlying post that his has content for
language (or language_id): This can either be the name of the language this content is written in, or a foreign key to a language table, with all the languages you've got content in. I'd be inclined to use language_id, but it's up to you.
post_title
post_content
...


In the post table, post_id would be the primary key, and an auto-increment value. In post_language, post_lang_id` would be the primary key, and an auto-increment value.