Hello Wolfgang, so if I follow your code examp,e what if I were to edit my code to be like this: \definefontfeature[generalfeatures][default][ kern=yes, % enables kerning extrakerns=yes, % enables extra kerning trep=yes, % Enables single and double quotes to show up correctly in text, perhaps does more liga=yes, % Enables ligatures. itlc=yes, % Activates italic correction. mark=yes, % Used for positioning diacritical marks (accents, dots, etc.) relative to base characters. mkmk=yes, % positions diacritical marks relative to other marks locl=yes, ccmp=yes, % Composes multiple characters into a single glyph or breaks down ligatures. mode=node, protrusion=yes, expansion=yes, language=dflt, ] \definefontfamily [myfonts] [rm] [Times New Roman] [features=generalfeatures,dlig=yes,cpsp=yes,% dlig enables times new roman ligatures, and cpsp is used by tnr, not aptos] \definefontfamily [myfonts] [ss] [Aptos] [features=generalfeatures,] \definetypeface [myfonts] [mm] [math] [stixtwo] [features=generalfeatures,] \setupbodyfont[myfonts,12pt] do you think this code is flawed? Also, do you think you could explain how locl and extrakerns works? do I need to have kern=yes for it to enable? how can I test if extrakerns Is working? when I just have kern=yes enable, and then enable extra, a pdf that has a paragraph using both in code looks the same. locl is something I'm completely unsure about.