I only wanted to add a note: XeTeX always converts, say, c + combining caron into a ccaron whenever one exists in the font (and does that on a really low-level). If ccaron doesn't exist (or if there's no such comination in unicode), it simply requests both glyphs from the font (and only modern fonts have those combining glyphs, I assume). In the case of LM, the font has combining characters with zero width with the accent shifted to the left, so that it looks OK on an average glyph (but in general, TeX does a better job with combining characters) unless one requests two accents. In my opinion, LuaTeX should also be able to handle such combining characters somewhere in the early stages (I have never followed the low-level details of LuaTeX - very often "low level" means "mkiv" for LuaTeX, so probably this still means - mkiv should handle that). So, either ccaron or c+combining caron (or l+combining tilde) should behave the same way: - if there's such a glyph in the font, use it - if there is no such glyph, combine the character from c and a caron (but probably not the combining one! - different fonts have different ideas of what a combining character should be) Also, {\v x} and other strange combinations don't work in ConTeXt (I guess it does in plain TeX) since ConTeXt MK II uses a clever way to figure out if such characters exist in the font encoding, but combinations of letters and accents that are not explicitely defined that they should work, are ruled out, which is a pitty. Mojca