[icc97]

If you use a lowly PHP MVC framework, you'll get I18N pretty much for free. It's just a customised echo / print statement. Same for any Django, Rails app. So if what you're using is more difficult than that I'd question what you're using to build your app. Admittedly React is pretty far behind for doing I18N. i18next [0], seems quite promising for that.

The app I built had no need for languages for the first 3-4 years. Then suddenly a foreign client comes in (ours is translated into Spanish, Portuguese, Russian and Chinese) and you've got a ton of code written.

[0]: https://www.i18next.com/#