Although vowels can be produced with manyF0 values, high vowels’F0s tend to be higher than low vowels’, a tendency found for every language examined. Nonetheless, this ‘‘intrinsicF0’’ (orIF0) has been called a deliberate ‘‘enhancement’’ of the speech signal, aiding vowel height perception. SinceIF0 remains constant with the number of vowels in a language, this enhancement seems unlikely. The only positive evidence for it is that activity of the cricothyroid (CT) muscle, which primarily raisesF0, is larger for high vowels than for low. The present experiment explores this by having subjects produce vowels at slightly differentF0s, with the differences being similar to theIF0 magnitude for each subject. The first subject (of four planned) showed no vowel height difference in CT; further, an analysis factoring outF0 as a covariate showed that high vowels had higher CT activation. Thus different vowels involve different levels of CT activity for a givenF0; previous findings were likely due not toF0 control but toF0/vowel quality interactions. Even the EMG evidence, then, rendersIF0 an unlikely speech enhancement. Rather,IF0 appears to be an automatic consequence of vowel production. [Supported by NIH Grant DC‐02717.]