Opal Dunn is widely known as a specialist in books on early first and second language development. She has been a consultant to the Council of Europe on children's bilingual education and acts as consultant to the British Council's LearnEnglish Parents programme. She has been short-listed for the Eleanor Farjeon award for services to children's literature and in 2008 received the Japanese Order of the Rising Sun for over 30 years work with bilingual Japanese children.

Opal's books for Frances Lincoln are Acker Backa Boo, El Gato Leo Goes to School, El Gato Leo Comes to Play, Leo le Chat Goes to School, Leo le Chat Comes to Play, Hippety-hop, Hippety-hay, Un Deux Trois and Number Rhymes to Say and Play. She lives in South London.