what percent of worldwide wealth is held by speakers of different languages?

[ajdamico]

per capita gdp x % who speak a language
adjusted by age (because bilingual people are poorer and younger) but also by income where available (because richer people are more likely to be bilingual)

[ajdamico]

in english-speaking nations, people who speak english+something else might be poorer while in non-english speaking countries they might be richer, adjusted for age