A good friend and I have a mutual friend from France who speaks English very well; however, some of our other mutual friends think that our French friend talks at a faster rate in English than native English speakers do. This brought up the question of whether or not certain languages are spoken more quickly than other languages...there does not seem to be a simple "yes or no" answer to this question. Here are a some of the various themes I came across while looking into speech rates:
Speech rate should be measured by the number of syllables per second.
Languages with multi-syllabic words tend to be spoken at a faster rate.
Speech rate should not be measured by the number of syllables per second because open syllables are spoken more quickly than closed syllables.
Speech rate is influenced by extralinguistic variables (sex, age, profession, emotional state).
Speech rate should take into consideration variations in continuity of speech.
An article in Language and Speech titled "Speech Rate in a Pluricentric Language: A Comparison Between Dutch in Belgium and the Netherlands," presents the findings of a linguistic study that, "confirms the traditional view that speech rate is determined by extralinguistic variables, but also suggests there may be intrinsic tempo differences between language varieties."
While I agree that extralinguistic variables affect speech rates across all languages, I think it would be fascinating to learn more about the tempo differences between languages, which obviously exist as well.