I don't think that the translation feature itself can be considered OS functionality. An API providing on-demand background execution time for apps linked to connected Bluetooth devices would surely be sufficient to comply with the DMA?
As an example, when they were compelled to allow competing browser engines, they didn't open source Safari; they added a multiprocessing/JIT API to iOS (tailored and restricted by policy to browsers). Competitors (web browsers) got access to the OS features (multiprocessing/JIT) that they needed to compete with Apple's product (Safari), but they didn't get access to the product itself and still need to build their own.
In this case, competitors (device makers) might request access to the OS feature (background execution) that they need to compete with Apple's product (live translation on AirPods).
It should also be noted that such functionality only has to be provided if explicitly requested by a developer who is working on a competing product, so they don't have to develop it preemptively.
I'm not saying that this is completely fair or whatever, just that I don't think it's quite as extreme as people are making it out to be?
(I’m an EU-based user of Apple products) I see your point. However, Apple already provides a translation API[0], a speech recognition API[1], and a Text2Speech API[2], so not a lot more is needed than the API you describe. Also note that, while I have not looked into that thoroughly, it seems the kind of API you are discussing shares many similarities with the features of the Apple Vision Pro SDK (real time computation introducing new constraints…)
I think this situation also shows a strong divide between two visions of Apple end-game (and I think both exist within the company): exposing those APIs makes the Apple ecosystem better as a whole, with its satellite accessories/app developers; while keeping them private gives them an edge as a hardware selling company. Personally, I prefer when Apple embraces its gatekeeper status.
[0]: https://developer.apple.com/documentation/translation/transl... [1]: https://developer.apple.com/documentation/speech [2]: https://developer.apple.com/documentation/avfoundation/speec...
> such functionality only has to be provided if explicitly requested by a developer who is working on a competing product
So if I'm Samsung, wouldn't I explicitly request every possible bit of functionality I could force Apple to provide, even if the "competing product" might very slow to market?