On the Powers of Internal Language

Much is written about the powers of what I call external language, or language that is used to have an effect on external reality, mainly on other people.

This has left me wanting for a resource that explores the powers of what I call internal language, or language that is used to have an effect on our own internal realities.

After all, what is the point of being able to use language to have an effect on others if we don’t know how to use it to have an effect on ourselves?