Each of these words has two pronunciations in divided usage in Standard English. Incomparable is usually pronounced in-KAHM-puhr-uh-bul when it means “beyond comparison, unequaled”; in-kuhm-PAIR-uh-bul, when it does turn up, means “incapable of being compared, beyond comparison.” Irrefutable normally has primary stress on the second syllable, but such stress on the third is also Standard; irreparable and irrevocable follow the same pattern. Some argue (although documentation is difficult) that there may be a slight but significant semantic difference between the two pronunciations of each of these three, analogous to that described for incomparable, but even if there is one, most listeners will likely ignore it in favor of the meaning they consider more obvious. See also -ABLE.
