The Languages of Pao (Jack Vance, 1958)

The Panarch of Pao is dead and Beran Panasper, his young son and heir, must flee the planet to live and avenge his father's death. It is at the secret fortress on the planet Breakness that Beran discovers the dreaded truth behind the assassination of his father-and much more. The people of Pao are a docile lot, content to live in harmony with the rest of the cosmos, but the scientists at Breakness seek to alter the psychology of the Paonese for their own purpose-and Beran holds the key to their audacious plan. Beran will return to Pao, transforming his home world beyond his teacher's wildest dreams. But though he has been fashioned into a man of Breakness, Beran's heart is of Pao. And he brings to his world the seeds of change that will save Pao...or destroy it.

Rating: 7/10

A similar book in which language plays an important role:
Babel-17, by S.Delany

The Durdane Trilogy (Jack Vance, 1970)

The land of Shant on the planet Durdane is ruled by a dictator called "The Faceless Man", or "The Anome". He is called this because his identity is literally unknown. He maintains control by virtue of the torc, a ring of explosive clamped around the neck of every adult man or woman of Shant. The invasion of Shant by barbarians will lead the protagonist of the book, Gastel Etwzane, to discover who the Anome is...

Rating: 8/10

The three books of the trilogy are:

- The Anome
- The Brave Free Men
- The Asutra

Lyonesse (Jack Vance, 1982)

The Elder Isles, located in what is now the Bay of Biscay off the the coast of Old Gaul, are made up of ten contending kingdoms, all vying with each other for control. At the centre of much of the intrigue is Casmir, the ruthless and ambitious king of Lyonnesse. His beautiful but otherworldly daughter, Suldrun, is part of his plans. He intends to cement an alliance or two by marrying her well. But Suldrun is as determined as he and defies him. Casmir coldly confines her to the overgrown garden that she loves to frequent, and it is here that meets her love and her tragedy unfolds. Political intrigue, magic, war, adventure and romance are interwoven in a rich and sweeping tale set in a brilliantly realized fabled land.

Rating: 8/10

The three books of the trilogy:

- Lyonesse (Suldrun's Garden)
- The Green Pearl
- Madouc

The Demon Princes (Jack Vance, 1964)