Edward Sapir explores the foundational nature of human speech, treating language as a complex, culturally transmitted system of arbitrary symbols rather than a biological instinct. He distinguishes true language from involuntary emotional cries and sound-imitative words, establishing that speech is an overlaid physiological function utilizing organs adapted for primary biological needs like breathing and digestion.
The inquiry proceeds to analyze the true elements of speech, moving from individual phonetic sounds to words, radical elements, and grammatical affixes. Sapir demonstrates that words are psychological realities that serve as counters for concepts, ranging from concrete objects to abstract relations. He examines how languages categorize experience, noting that grammatical categories often operate as fixed dogmas that shape thought.
Phonetic habits and the inner sound-systems of languages are examined to show how sounds function within formal patterns rather than as isolated acoustic events. Sapir details the primary grammatical processes used across human languages, including word order, composition, affixation, internal vocalic and consonantal change, reduplication, and accentual differences.
The structural classification of languages is approached through conceptual groups rather than mechanical categories, distinguishing pure-relational languages from mixed-relational ones, and analyzing degrees of synthesis and fusion. Sapir emphasizes that no single language represents a pinnacle of evolution, as all linguistic structures are flexible systems shaped by historical drifts.
The final sections trace how languages change over time through continuous phonetic and morphological drifts. Sapir analyzes the gradual nature of phonetic laws and the steady erosion of inflectional systems, demonstrating how unconscious shifts in usage reshape the structural genius of languages across generations without direct speaker intent.
