This book lays the foundation for the author's future linguistic research. Unlike other researchers of the same period who relied on the linguistic model of the former Soviet Union, Professor Nguyen Quang Hong embraced the Chinese tradition of phonology, thanks to his years of study at Peking University. In this work, the author examines Vietnamese as an independent language: each syllable is not only a unit of pronunciation (as in European languages) but also a unit of meaning, with the status of an independent word. By affirming the role of syllables in constructing speech and utterances, Vietnamese is studied in full, highlighting its unique features. These theoretical foundations have had a significant influence and have been applied in many studies by subsequent generations.