You cannot know for sure, you can only guess. There are thousands of engineering companies in the world from Japan, China, India and other countries that conduct a complex technical dialogue only in English. I know this for sure, because the company I work for is doing just that. We employ translators who know English better than some of its native speakers and can easily translate any drawings and technological documents.ispano6 wrote: ↑Wed Feb 24, 2021 6:52 pmI don't believe, I know. How many Japanese drivers in the current F1 hybrid era have driven the Honda power unit to be able to give detailed feedback to Honda engineers? Just one, when Yamamoto Naoki drove for Toro Rosso in Japan FP1. You see, Japanese people who speak only Japanese are terrible at English, and believe it or not even the ones who do speak English well can only translate the English they hear and understand into a very basic translation to Japanese. The nuances in the language often times don't translate either, because some of them just don't have the equivalent ways of saying things. Listen to the talking speed and amount of vocabulary Tsunoda uses between English and Japanese. His diction is limited to his English, where as his Japanese flows out.
Tsunoda played in the European team and won races, which means that his level of English is quite sufficient to explain to the engineers what he needs. And there are many European riders who race in Japan or on Japanese teams who don't know Japanese but have very successful racing careers in that country.