Thanks. I get the dots above/below, if I load xunicode package "before" fontspec. If I use it after the fontspec, nothing happens. Also, the dots are not centered properly above or below the characters. The dot below using \d{} is somewhat satisfactory, but the dot above using \.{} is way off the character too much shifted to left/right.
Here is the test file: \documentclass{article} \usepackage{xunicode} \usepackage{fontspec} \def\tam{\fontspec[Script=Tamil]{Latha}} \begin{document} \tam \d{{ரி}} \.{{ரி}} \end{document} -------------------------------------------------- Subscriptions, Archive, and List information, etc.: http://tug.org/mailman/listinfo/xetex