Verbs are always stressed on the last syllable of the word itself, and the first suffix is never stressed. If, after that, there are any suffixes which end in ' then they are stressed, too. There is an exception to the above: If a speaker wishes to emphasize a particular suffix (as is often the case with the interrogative suffix and suffixes for negation and emphasis) then stress may shift to that suffix and leave the rest of the word unstressed. Also note that adjectival verbs are stressed in the same way as other verbs.
Nouns are usually stressed on the last syllable of the stem. But if there is a syllable in the word, or any of its suffixes, which ends in a ', then that syllable is stressed instead. If there is more than one such syllable, then they are all stressed. Also note that nouns made from a verb plus -wI' or -ghach are stressed as nouns.