Engelmann on teaching deaf children

Ken found this passage in Chapter 4, pp. 11-22:

Although we abandoned the vocoder, we continued to teach deaf children language, using our beginning language programs. In most settings, children use a signing system that has provisions for indicating word order, tense, and number (American sign syntactical). In other words, children are generally not responding with verbal responses, but with signs that convey the syntax of the language. The beginning language program sets the stage for teaching writing and extended vocabulary. One of my associates and co-authors, Don Steely, was involved in several experiments that showed the enormous performance differences between middle school and high school classrooms that use the Direct Instruction approach and those that follow the traditional recommendations of deaf educators. With a good language-instruction sequence, we can obviate many of the problems children have in writing passages that are syntactically acceptable.

Unfortunately, this passage, too, is over my head.

sigh

He doesn't seem to be talking about a method of signing phonemes.