Could you please tell us a bit more about your aim when asking for markup languages. There are markup languages like html to show content in webbrowsers or other ones to simplify the creation of structured text files or to convert a textfile of one file-format into another file-format. Here I want to mention the Markdown-language (md) which comes in different flavours.
A popular software for dealing with md is Pandoc (open source!). Pandoc can convert file formats between pandoc-md, html, docx, odt, LaTex, pdf.
With pandoc md you can setup an easy readable text as source and convert this into a LaTex file without knowing LaTex syntax. You only need a couple of md-syntax to style texts.