Update. The authors of the previous piece in this thread just released a summary.
https://theconversation.com/prestigious-journals-make-it-hard-for-scientists-who-dont-speak-english-to-get-published-and-we-all-lose-out-226225
"Linguistically inclusive policies come in many forms, and can be implemented at each stage of the editorial process. They might aim to make publishing more #multilingual. Alternatively – if sticking with English – they may aim to reduce the burden on non-native English speakers."