The Giants and the Joneses.

A charming story for 7 - 11 year olds, which tells the story of three human children (or iggly plops in giant language) and a girl giant, Jumbeelia, who first collects and then neglects them. Stranded in the land of giants, the Joneses find themselves at the mercy of Jumbeelia's sadistic brother Zab, and have to draw on all their resources to hatch an escape plan. The book features an invented language, Groilish, and there is a dictionary at the back.