English-language journals also, inevitably have editors and advisors who speak, read and write good academic English. It is not as easy to trace the language of conferences, but English is certainly the dominant language of conferences. A bilingual conference is usually in the teaching language of the host university, plus English. Organisers often require papers in English, even if most of those present understand other languages. In effect this fixes the language of contact as English.
Multilingual journals are rare.