TeX is a typesetting software popular in the scientific world for producing high-quality documents. The newest versions support Unicode and opentype fonts and can generate multilingual pdf output. The learning curve is steep, however, because TeX is the opposite of WYSIWYG and the user needs to know a lot of commands.
If you want to give it a try, download and install the large or small packages from here. Open TeXShop, set the mode to XeLaTeX, and choose the XeLaTeX template. Toward the bottom you will see how you can name fonts and test text in various scripts. Hitting the Typeset button will generate a .pdf. I tried adding Hindi, Tibetan, and Egyptian Hieroglyphs and it seemed to work fine.