'designers must understand acoustic memory and prosody' ...

Since speaking consumes precious cognitive resources, it is difficult to solve problems at the same time. Proficient keyboard users can have higher levels of parallelism in problem solving while performing data entry. This may explain why after 30 years of ambitious attempts to provide military pilots with speech recognition in cockpits, aircraft designers persist in using hand-input devices and visual displays. (the limits of speech recognition)

instead of getting annoyed of these call center programs, just don't press any button and you get forwarded to a human being. that's their build in fall back solution for angry and frustrated user. (haven't found one where that wasn't the case and it takes the same amount of time anyway.) i think it reduces occurrences of situations, where someone tries to shrink human beings to click puppets.