This book is very thorough, but at times it seems like the authors go out of their way to keep their discussion on a very theoretical level. Chapter 1: A highly theoretical review of DSP. You need good knowledge of DSP to understand it.
Chapter 2: Goes over the human speech production and recognition systems. Here you get some practical info on the spectral and time-domain properties that distinguish speech sounds.
Chapter 3: Describes a model of the speech production based on a series of pulses passed through filters that correspond to features of the human speech production system. Practical issues such as which zero and pole values work best are left as an exercise to the reader.
Chapter 4: A lot of mathematics relating long-term statistical properties to those of a short frame of speech data. Contains good info on how to find recursive formulas for statistical properties of speech frames. It is a great shame that the authors don't include examples in MATLAB or pseudo code.
Chapter 5: Linear Prediction. Discusses a mathematical algorithm for creating a prediction filter that could be used to predict the next value in a series of data. In speech processing we are interested in using the coefficients of this prediction filter to encapsulate the properties of a speech frame. Examples of 1st,, 2nd, and 3rd order filters would have gone along way to illustrate how to implement this. There are some good formulas to measure the degree of similarities between speech frames based on their LP filter coefficients.
Chapter 6: Introduces the concept of the cepstrum. Cepstral analysis allows you to de-convolve speech data to separate the excitation source from the vocal tract filter. That way you can lifter out (a play on filter out) the excitation (responsible for pitch) and focus only on the vowel sounds. As always, how to make it work is left as an exercise.
The rest of the book is about speech coding and speech recognition. My class did not cover the later chapters, so I only read the parts that applied to projects.
The book helped me understand speech processing journal articles which tend to assume a lot of background knowledge.
The theoretical background that this book provides is necessary; good engineers need to understand the underpinnings of their bag of tricks. It is painful, however, at times. To apply the information in this book, you will certainly need a good mentor and a lot of tinkering in MATLAB.
