Transformational Rules change the basic structure of the Kernel Sentences in English
Transformational Rules: There are many ways to change the basic structure of these Kernel sentences-- to streamline them and make them fit the intent of the communication more efficiently and effectively.
The rules for changing them are called Transformations. There are many of them and they can be quite complex. The Yes/No Question Transformation is a good example.
Take the rather simple sentence: "I go."
How would you change that sentence into a question without adding to the meaning?
If you said, "Can I go?" you are pragmatically correct, but semantically incorrect, because you have changed the meaning by adding the notion of "capability."
I was thinking of the sentence, "Do I go?"