Bilingual FR/EN blog in pure PHP: architecture without framework or database

This blog was built in pure PHP, no CMS, no database. First article in the series, already published. At some point the question comes up: is it worth adding English support? Short answer: yes, and it's less complicated than it looks. Long answer: here's how I did it, with the traps that come with it. No gettext, no i18n library, no database for translations. Just separate PHP files per language, a restructured JSON file, and three layers of routing. The whole thing fits in a few dozen lines of...