Speaking fast or slow, most languages convey the same amount of information in a minute due to the correlation between data-density and the syllables per second of speech. This means someone speaking high data-density language (like English) and a low data-density language (like Spanish) will still communicate the same amount of information in a minute, even though one sounds much faster:

English, with a high information density of .91, is spoken at an average rate of 6.19 syllables per second. Mandarin, which topped the density list at .94, was the spoken slowpoke at 5.18 syllables per second. Spanish, with a low-density .63, rips along at a syllable-per-second velocity of 7.82. The true speed demon of the group, however, was Japanese, which edges past Spanish at 7.84, thanks to its low density of .49. Despite those differences, at the end of, say, a minute of speech, all of the languages would have conveyed more or less identical amounts of information.

via Kottke