Authors instruct the readers to misspell speechSynthesizer as speechsynthesizer to show that no delegate method will be called and the compiler will issue no warning or error. The authors assert that the Stop button can never be enabled. In reality, the Speak button will not be re-enabled after speech stops. Also of note: the windowShouldClose(_ will always return false once speech has started.
print page 114, iBooks page 253 (Portrait)