Writer-director Guy Jenkin does nothing to revolutionize a familiar tale in The Sleeping Dictionary. The story is the stereotyped tale of forbidden love between two individuals from diverse backgrounds. It is about John Trescott, a young, uptight British officer, who is sent to Sarawak from Britain. He is interested in native customs and vies to teach the locals how to excel in knowledge. However to communicate with them he has to know their language. He is introduced to the custom of the sleeping dictionary where a native woman becomes his guide to learning the language as well as his personal concubine.
John embodies strong conservative values. Therefore instead of taking advantage of the situation he rejects the idea. As a result of this there is plenty of tension and bad blood between him and Selima, the beautiful native woman who had been assigned to live with him. However as time passes they become slowly accustomed to each other and fall in love.
Marriage is off limits with the natives though Englishmen are allowed to bed their women. Even though John tries to legalize their relationship duty send him abroad to be married to a British girl. He returns after a year with Cecilia, his wife. Selima and he set eyes on each other again but both have different partners. They are able to rekindle their love in these circumstances and John makes the shocking discovery that he has a son by her. Just when he is about to start a new life again, the tables turn. Cecilia too is pregnant. John is faced with two choices: to continued with his marriage or to lead a life of exile with Selima.