Rakuten Inc. CEO Hiroshi Mikitani is happy with the improvement of his workers' English proficiency and all employees understand its importance as the company expands globally, he said Friday.

Rakuten will mark the formal beginning of what it calls the "Englishnization" project Sunday. Employees will be required to speak English during all internal meetings and draft all internal documents in the language. The preparation period started in May 2010.

"Some people even became better than me" in the past two years, the MBA holder from Harvard Business School said in a news conference in Tokyo. He also said the positive impact will exceed short-term costs to let employees study English during work hours and take longer to prepare English documents for meetings.