I have searched for a simple method to allow a user to highlight a specific piece of text with a user chosen color but have not found one readily apparent. I have found a few methods related to syntax / code highlighting. I am not trying to highlight code but merely text within a blog post. Preferably I would like a simple method that provides a UI button within the editor itself as some users that post articles are not technically savvy and may have issues with short codes. I am currently running Wordpress version 3.5.1.
While I rarely recommend plugins, the CKEditor plugin will do highlighting of selected text. That sounds like exactly what you want. And it is a greatly enhanced editor relative to the default one. Short of creating your own editor buttons and supporting functions, that would be a pretty good choice.