Tsao's work required him to deal with books and documents from the US, Europe and Japan on a daily basis. He'd studied German with his wife's brother Zhang Yu before he started at the library, which helped him a great deal when he began working with Dutch documents.
因為工作，曹永和每天必須接觸歐美日各國書刊文獻，進圖書館工作前，他就跟妻舅張鈺學過德文，由於德、荷語出同源，學德文的基礎，對他日後研讀荷蘭文頗有幫助。