The out of the box links don't specify language at all, so there is no way with an internal item reference to specify a specific language. The link is tied at the item level, not the version. Similarly, you can't directly link to a specific version of the content in the current language.
When invoked, the LinkManager uses the current context language for building the URL in a Rich Text field from the internal link. If you want to override this behaviour, you'll likely have to do the following:
- Add two fields on your content: one for the link, and one for the target language
- Write custom logic to output the link field and use the selected target language as a parameter for the LinkManager URL options.
NOTE: If you are using display name for your URLs, you might have to load the item in the target language and pass that target item into the LinkManager as your different languages might be outputting different URLs. If you only use the Sitecore.Context.Item for the parameter you will always get the path for the current language, and not the target one.