SOLVED. A novel about a language deprivation experiment

[Lara]

This is a literary novel about a man who wants to replicate the "forbidden experiment" of raising children without language. He impregnates a woman and she gives birth to twins I think, whom he raises in isolation, never allowing them to hear speech. The twins develop their own invented language that they use to communicate with each other. The sadistic father at one point breaks one of the children's arms to see how they will react. A very disturbing novel - can't remember the title or author.

[Lara]

I found it! The Dumb House by John Burnside.

[Rainbowheart]

The Dumb House for the link.