My son starts Middle School in September. We just got a flyer from the school board asking him to choose a foreign language class. The choices are: French, Italian, Spanish.
My advice to him (which of course he will ignore) is just to be hard-headed about it & pick the language most likely to give him an "edge" in future employment.
That rules out Spanish, since the USA is choc-a-bloc with Spanish-speakers, so the market value of this skill must be low.
I don't know where Derbyshire lives, but in my neck of the woods it would be very helpful to speak Spanish if one wants to do anything at all in the community... for example, if one wants to open a small business.
Or to put it another way: The USA is already "choc-a-bloc" with English speakers, and the market value of that skill is commensurately very high.