The correct constant is ICL_LANGUAGE_CODE :
http://wpml.org/documentation/support/wpml-coding-api/
Prefixing is not really maintainable because I don’t know which languages our client will add… And can become a mess.
Creating a “global variables page” is what I was doing before using ACF Options… So I’d rather not regress 😛
For now I think I will replace “translatable” fields in the Options page by Repeaters ones, in which the key will be the language code.
It’s a shame that it’s not better handled, is it on your roadmap to enhance this Elliot ? It’s really a pleasure to work on complex and multilingual sites with ACF and WPML, except this part 😉
