In some companies in Japan employees are required to speak English.
The word requirement means that you have to do it or you need to do it. So if companies require employees to speak English then they have to speak English or learn to speak English.
There is an emerging policy in Japanese companies, where spoken English is mandatory
Mandatory: Obligatory, compulsory, binding, required; (There is no choice) Given that English will be spoken by 90% of the population within 5 years...This seems like a strategy in order to deal internationally... "There is an emerging policy in Japanese companies, where spoken English is mandatory"
Mandatory: Obligatory, compulsory, binding, required; (それしかない!義務と言う意味ですね)
5年以内に全人口の90%が英語を話すようになるという事を考えると、
国際化を考慮に入れた戦略のようですね。
【例】
"There is an emerging policy in Japanese companies, where spoken English is mandatory"
(社内英語公用語は日本企業に表れつつあるポリシーです)
making English the official language in the workplace
English as the official language in the workplace
making English the official medium of communication in the workplace
公用語 = official language
社内 = in the workplace (他のシチュエーションで、"within the workplace", "internal", もしくは"within the company"にも言えます。)
通信媒体、通信方法 = medium of communication (こちらの mediumはサイズのメヂアムではなく、「方法」の意味です。)
1と3番目の提案は動名詞なので、文章で使ったら、文章によって形がかわります。
例えば: Uniqlo, Rakuten, and other companies have made English the official language in the workplace. (ユニクロ、楽天や他の会社は英語公用語化をしました。)
(短く言いたかったら、official workplace languageでも大丈夫です!)