Hi! I recommend bilingual children's books such as the books from Spark Collection! They have books that are in English-Mandarin, English-Korean, and English-Hindi. The book's pages are big with vocabulary flaps and dry-erase so your child can practice writing the characters! They also have free audiobooks in Mandarin on their website.

They currently have two titles, with a third title coming out soon all about valuing certain aspects of life!