Learning Languages (by a monoglot)
My basic education included 11 years of French classes, and I don’t know any more French than ’le chat’. Those lessons could hardly have failed harder in Britain’s schools.
I recall the counting in Maths, and most people can square something, and understand what, roughly, Maths can do. I still read well, so evidently English classes were a good use of my time. So French class does not show a general pattern for us to forget our education once done, it has a special place - last.
People cannot speak French in the UK, because French people do not very often live in the UK. We could have learnt Polish, Hindi, or British Sign Language (BSL), the vast majority of children would later encounter speakers of that language.
The ease of learning a language always equates with how close it lies to languages one already knows.
Consider a Pole learning another language. Step over the border, and you’re hearing Czech - it’s bizarre, but with a few extra rules you can understand what’s written, once you read slowly. A few months later, and you’re conversing in basic Czech. Six months after that, you’ve travelled to Slovakia, picked up a couple of changes in a week, and officially learnt your third language. Later, you can go to Slovenia, and spend enough couple of months for yet another language.
Now look at the poor English speaker. The closest neighbours (Afrikaans, and Dutch) won’t speak with them, because both already know English. The third-closest neighbours (German) still intimidates them, with its cases and memorized-genders.
Ladders and Rungs
Learning French takes a native English speaker an average of four years. Learning Esperanto takes one. But someone who knows Esperanto and English can reach French fluency in 2 years, meaning that learning Esperanto, then French, takes 3 years, while learning French takes 4.
Having a useful second language may initially seem like a good idea, but none of the students will emerge actually speaking a new language, so if language classes can have any use, they must have some use aside from learning a language. I imagine the best choices would either be BSL or Toki Ma.
BSL allows children to speak immediately, at least about simple, physical, subjects. They have a language which everyone can use in noisy environments, or in Maths class when they should be studying.
Toki Ma fulfils a similar role to Esperanto - it lets people experience speaking a new language without learning two thousand basic words. Instead, Toki Ma only has about 200 words, and constructs the other ideas from those base components (‘silly water’ = ‘alcohol’, et c.).