WordNet sense 1 (special importance or significance):

emphasis

WordNet sense 2 (the usage or vocabulary that is characteristic of a specific group of people):

dialect, idiom

WordNet sense 3 (distinctive manner of oral expression):

speech pattern

WordNet sense 4 (the relative prominence of a syllable or musical note (especially with regard to stress or pitch)):

stress

WordNet sense 5 (a diacritical mark used to indicate stress or placed above a vowel to indicate a special pronunciation):

accent mark

WordNet sense 6 (to stress, single out as important):

accentuate, emphasize, punctuate, emphasise