The Smallest Possible i18n: One JavaScript File, No Framework, No Build Step

I have a static HTML site — no React, no Vue, no bundler, no build step. cp is my deploy tool. I wanted to translate the whole thing into Japanese, Chinese, and French. Every i18n tutorial I could find assumed a framework. react-intl, vue-i18n, Next.js s next-i18next, formatjs — they all want either a component model [ ]