…how many languages they know. Does it count as knowing a language if you can only say “three elephants all stepped on the same peanut” in it? If you can’t even say that, but at least know whether and how they normally distinguish between that and “three elephants each stepped on a peanut”? If you can translate almost everything, but at a rate of a word per minute? Do English and African American Vernacular English (“ebonics”) count as separate languages? Do Dutch and Low German? (The latter two are actually closer in structure (and possibly even in mutual intelligibility?) than the former two, but only the latter two have armies and navies.) From another perspective: it’s like asking an astronomer how many stars they know.