While I agree with your premise, it's not wrong to think of it the other way too (especially in terms of numbers as opposed to percentages)
Nevertheless, 13% of the US population are native Spanish speakers[1], and presumably more have some level of reading skills. Hard to judge overlap with HN readership, but it's probably fair to think that 4-5% of your sites readers can read Spanish.
Low. Very low. Think about the Hispanic population a little.
> but it's probably fair to think that 4-5% of your sites readers can read Spanish.
If they are, they aren't setting their OSes or browsers to use Spanish rather than English... An 'es' language code doesn't even show up in my GA language headers until #13 (consistent with the geoip), putting them at ~0.5% of all hits. I have more German, French, and Russian-preferring readers than Spanish (which is only slightly more popular than Portuguese). HN is cosmopolitan, but all the evidence I have is that it's not in a Spanish sort of way.
You see many Spanish-speaking countries listed...?