Complex sentence: According to the book, Nazi scientists, believing that canines were almost as intelligent as humans, set up a special school named "Tier-Sprechschule ASRA" to teach the dogs to speak and spell so that they could communicate with their Schutzstaffel masters.
Split into simpler sentences: According to the book, Nazi scientists believed that canines are almost as intelligent as humans. A special school named "Tier-Sprechschule ASRA", was set up to teach the dogs to speak and to spell in order to be able to communicate with their Schutzstaffel masters.