[adventured]

American cultural projection and economic success in the 20th century is overwhelmingly responsible for spreading the English language to so many corners of the globe. The British Empire collapsed and retracted back to the UK. Britain's global cultural projection is a small fraction of the US today. If eg Britain were the primary driver of English since WW2, as the first major sponsors of the language, you'd more likely see a contraction in English in line with the contraction of the British Empire and their cultural + economic reach. Instead English has continued to spread.

People in China haven't been aggressively learning English the last ~30 years primarily so they can do business with New Zealand. English become the global language of commerce because the US took over nearly half of the global economy, and over half of its manufacturing, immediately after WW2.

It's pretty simple: the British started that fire, then their empire declined. The US picked up their torch and made the fire a lot bigger with the wide-spread globalization we see today coinciding with the US becoming the sole superpower post WW2 (ie produced a perfect storm for English spreading globally).

[notahacker]

I'm not sure English would have "retracted back to the UK" even if the US spoke Navajo as its preferred language. It's not realistic expectations of doing business with the US or watching Hollywood instead of Bollywood that explains why English became the alternative to Hindu dominance of language in Indian education, commerce and civil service. The much earlier decline of Spanish colonial influence didn't diminish the pervasiveness of its language in certain parts of the world (most where English is seldom spoken) in any meaningful way, and there really aren't any obvious corners of the globe English hadn't already spread to some extent before American cultural influence kicked in.

There's a reason why people haven't been aggressively learning Chinese despite it being the language of the world's #2 economic power, and that's because all the boots on the ground work to set up civil services, education systems and trade networks and associate their language with prestige and power had already been done by colonialists speaking other languages.