A French study study published by the University of Lyon has shown that Spanish (after Japanese) is the fastest spoken language, although it is also the one that transmits the least information per second. That is Spanish speakers talk faster than people who speak English, Italian or French, but transmit less information per second.
Spanish is spoken at an average of 7.82 syllables/sec, while the average English speaker will speak at 6.1 syllables/sec.
Take for instance the two-syllable Spanish word feliz (happy), which is made of two syllables that don't independently carry any meaning. While the two-syllable English synonym blissful, is composed of two syllables that independently deliver lots of information - "bliss" means perfect happiness, great joy.