Are you trying to reduce the translation json file size?

Yes, with the idea being that a smaller JSON file size would result in a faster initial page load.

If yes, then it traditionally has never been a bottleneck

It may not be a bottleneck, but many things in our application are not. Yet, optimizing certain things is cheap and performance is important for us; shaving even milliseconds off our initial page load could result in more views and better SEO rankings. It also creates a bit of a cognitive dissonance for me when we decide to split our JS and CSS bundles, invest in SSR and SSG, but then forego the same treatment for a very large and growing translations file based on the intuition that it may not have been a problem for other projects.

I ran some cursory tests on loading our translations file vs. splitting it up, and the performance data suggests splitting it up improves initial page load. Your response has prompted me to better consider the tradeoffs and performance gains here–perhaps we'll make sure to gather more robust performance data.

it also has a very high TTL.

I didn't think about TTL. When you say it has a very high TTL, do you mean that developers generally set certain Cache-Control directives (e.g. a high max-age value), or that the CDN could be configured to handle translation files differently?

I'd recommend you throw it on the CDN, do versioning, load it separately and treat it as any other assets.

Thanks–all very good ideas! We do take advantage of a CDN and caching is definitely our friend. I will have to make sure we properly version our translation files, possibly appending a content hash to the name on generation.

Additionally when we deal w/ dep tree walking we naturally have to deal with path aliasing, symlinking and a bunch of other rabbit holes that are path-related.

Totally understandable, and laudable, especially considering the difficulties you enumerated. I'm a fan of the unix philosophy and avoiding software bloat / the "second-system effect", so I'm happy you provide the tools to allow me to experiment with loading split translation files 😁