We report on intrinsic fundamental frequency (IF0) differences in Butlih Salawati and Biga, two closely related Austronesian languages. Both languages have small inventories of six underlying vowels; they both also have simple tone systems, with two specified tones. We show that IF0 differences between high and low vowels in the languages range from 1.5 to 2.8 ST, depending on tonal specification and utterance context. Overall, these results are larger than the mean crosslinguistic difference of 1.65 ST. Based on the previous literature, strong claims that IF0 is under the control of the speaker predict that IF0 differences are attenuated in tone languages, and not enhanced in languages with small vowel inventories. The results presented here do not support these claims. However, we suggest that these results may explain the comparatively frequent tonal developments conditioned by vowel height attested in Austronesian languages.