The period witnessed a decisive move from articulatory descriptions toward discrete feature-based representations of phonemes, using binary features to capture contrast. Cross-language studies and perceptual experiments highlighted language-specific cues and categorical perception, broadening the scope beyond English-centric analyses. Coarticulation evidence further suggested a dynamic, gestural dimension to phonology, integrating production and perception into a unified framework. Historical Significance: This era established a durable paradigm—the feature-based approach—that organized phonological analysis for decades, enabling systematic cross-language comparison and formalization of phoneme structure. It laid the groundwork for later theoretical developments and computational modeling, and it anchored coarticulatory and gestural perspectives as integral components of phonology. The insights into categorical perception and cross-language variation reinforced the importance of empirical data in shaping theory and informed subsequent research trajectories in phonology.