I believe the quote is referring to Digital pins, but I am not 100% sure.
I believe the device that reads the analog pins voltage and converts it to decimal is completely separate from the device that controls the digital pins. So, the sampling rates are probably not the same.
There has been someone who has already looked into the sampling rates, but it seems he did not get his question answered either:
Sampling Rate of the Analog Inputs
He had another thread that has been either deleted, or has gone missing. In that thread he seemed to indicate that the sampling rate was 7 ms.
I took his code from that thread, and modified it to test multiple reads in a row. What I see is that the reads take about 8.6 milliseconds. Doing them one after another did not seem to help, still about 7-8 milliseconds. Which is about 100 Hz.
Attached is the sketch that I used to measure the time.
A better method for sampling Audio would probably be USB audio device. Of course, that could be done at the Linux level, and then you would need to figure out some way of getting it to the Android side. Or maybe the best option is to just work in the Linux side? There are Siri clones on the Rassberry Pi. I would hope they can also be run on the Galileo, though, I have not heard of anyone trying that yet.