For superhumans, Heinlein ("Gulf") suggested that base 60 would be suitable. With the 60 digits also doing duty to represent the 60 phonemes of a new language, there would be 216,000 words of just three letters, most of them monosyllabic. With the speed of speech and thought this would make available, effective lifespan would be extended by many times.
[Flerdle] 11 TimTams to a packet? The only packet I ever see has a hole in the cellophane and only 10 in it. BTW, The National TimTam vault is now replenished. They're back in the country.
[Raak] Are there 60 phonemes which the human voice can produce? I thought there were far fewer. (And I wrote a speech synth once, if that gives me any credibility, which I doubt!)
[Darren] Many more than that, if you add up the inventories of all human languages. Of course, you might have to be a superhuman to reliably distinguish them all. English has between 34 and 50, depending on how you count them.