Let me narrow the discussion down to one of the more widely known Nahuatl names Nezahualcoyotl In Spanish this is usually but not always written Nezahualc yotl The Nahuatl Wikipedia does have an entry for him nah Nez hualc yotl with horizontal accents over the vowels However there seem to be very few English Google entries which use accent marks The Encyclopedia Britannica article has no accents fr instance I would suggest that we should either use the two vertical accents as per Nahuatl Wikipedia or none at all I completely dislike the idea of following the Spanish example since Nezahualcoyotl was not Spanish in any way and this is not a Spanish language dictionary