On a full size keyboard? Most veteran typists can put down words at or above natural speech rate, especially the somewhat slow and stilted speech that seems to work best for those dictation software packages.
Do you have a citation of some sort for this? Seems a bit far-fetched unless it's a person that specializes in typing language very fast. I've used computers for >8 hours a day for two decades, writing a lot of long texts in that time, and I'm nowhere near being able to type as fast as I can talk. Certainly not when it comes to a sustained pace for more than a few minutes.
Cool, thanks :) I agree that comparing dictation speed to typing speed is a different question if you're a fast typist. On a phone, it's no contest -- for me, even in my native language, dictating with Siri is vastly quicker -- but I wouldn't actually want to dictate when I write comments online, for instance.
When dictating, you also hit the classical problem of your thoughts not forming fast enough to be able to formulate yourself in writing in real time, leading to a lot of breaks as you dictate. The guideline "think, then speak" of radio communication also holds for dictation, in my experience.
Let's not forget languages that aren't ideally served by qwerty - I'm thinking asian languages in particular. Even therein, there's chinese, which has a high semantic density to syllable count, vs say japanese, which requires more syllables* to say the same thing.
*more keystrokes but same time spoken, as the natural speech cadence is faster. Can't remember source right now.
Of course those Asian languages that are difficult to type are also difficult for speech to text programs, especially ones like Japanese where understanding the context is important for choosing the correct glyph.