Another great article...this is apparently a hot topic in linguistics research.
English has ~7000 distinct syllable sounds? That seems crazy. This number must include all the many regional differences of the spoken language. Even so, wow that's a lot of distinct sounds. There should be a study out there explaining why there is such a wide disparity in the number of sounds among languages. English has certainly been affected over the centuries by migrations of peoples and diverse cultural influences; perhaps that is a factor.
At what I'm guessing is the opposite end of the scale, Japanese comes in at 300 distinct sounds. This is also very interesting, because my understanding is that Japanese, as represented in kana, is a language with shallow orthography, meaning roughly that what you read is what you can expect to hear. The syllabary in my Minna textbook, which I think is a fairly standard representation, contains 103 different sounds. But I suppose when you include things like 長音, 促音, 撥音, 鼻濁音, and other sound modifications, the number rises from 103 as represented in Minna's expanded 五十音図.. The number 300 is small enough, however, to be represented efficiently in a table of some sort, and I'm sure some linguistics textbook has done just this.
Getting back to the subject of the speed of the spoken language, this study also seems to confirm the layman's perception that some languages are indeed articulated faster than others. The variable is thought to be the information density of the syllable in a given language. I seem to recall from the podcast you alerted us to previously, nahadef, that Japanese was an outlier of this hypothesis according to (another?) study, but I can't remember precisely.
This is a fascinating subject, isn't it?
Thank you for the link!