Good English - both written oral - the PI is not a fluent Chinese speaker.

英语写作和口语良好——因实验室领导人汉语不流利。

youdao

There will be a test of both oral and written French.

将有一次法语口试和笔试。

《牛津词典》

His grammar and syntax, both in oral and written expression, were much better than the average.

无论在口头还是笔头上，他的语法和句法都非常出众。

《柯林斯英汉双解大词典》

Malian Ambassador to South Africa Sinaly Coulibaly said that while African history and culture were often associated with an oral tradition, the Timbuktu documents were a reminder that African knowledge comprises both a written and oral tradition.

BBC: Decorated manuscript

Strong communications skills, both oral and written.

UNESCO: Vacancy : Human Resources Officer (right to education) (30/1/2012) 1CAUIS0030ST - (P-3)