Using the Blog Post widget should work for you. If your blog posts have the translation for the language the user selected then it will show the proper language link, if no translation then there will be no link for that post.
Sorry I re-read your title of this post a realized my above statement was not what you wanted. That said adding a navigation widget to the blog page template would work also. Assuming that the page you select has the translation the user selected it will route them correctly.