This book presents physical theory of speech production contained in Acoustics of Speech Production by R. S. McGowan and On Formants by R. S. McGowan in a largely non-mathematical way. New mathematics is presented in Appendices. There are a series of linguistic examples that are present illustrating how the physical theory illuminates understanding of phonetic processes, and, to some extent, phonological models. The physical theory is presented as mechanics instead of the usual electrical analogs, and it covers both the filtering of acoustic waves, as well as sources for the acoustics, such as voicing and air turbulence. Tissue vibration during speech is also reviewed. The linguistic examples include issues in speech development, vowel acoustic sensitivity in studies of delayed auditory feedback, hyper-articulation, and vowel tenseness. Also source-tract interaction, weak fricatives, future inverse modeling, and speech perception are considered.