Prose passages read aloud or silently were rated for pronounceability and comprehensibility. The relationships of text-derived readability indices to reading rate, comprehensibility ratings and comprehension test scores were explored. Reading rate in syllables per minute was unrelated to readability. The high correlation between rate in words per minute and readability was attributable to the syllable-rate constancy. Consequently, syllable rate appears to be the more prudent measure for research relating readability to rate. Comprehensibility ratings and comprehension-test scores were moderately correlated with the readability indices. This finding underscores the need to isolate additional text-derived predictors of readability. (Author)