Vocabulary is a central resource in language learning because it provides the lexical means through which learners interpret texts, construct meaning, express ideas, participate in interaction, and communicate in academic and professional settings. Yet vocabulary knowledge is often reduced to the memorisation of isolated words or dictionary definitions. A more comprehensive view treats vocabulary as multidimensional and incremental: knowing a lexical item may involve knowledge of its form, meaning, pronunciation, grammatical behaviour, collocations, word-family relationships, register, contextual restrictions, and ability to retrieve and use it appropriately. This conceptual article examines vocabulary development and its relationship with reading and speaking, with particular attention to learners of English as a second or foreign language and to the needs of higher education. Drawing on established vocabulary scholarship and recent literature, the article discusses vocabulary breadth and depth, receptive and productive knowledge, contextual learning, deliberate and incidental learning, extensive reading, repeated encounters, retrieval, morphological awareness, collocations, lexical chunks, dictionary use, and digital learning resources. It argues that vocabulary and reading have a reciprocal relationship: lexical knowledge supports comprehension, while sustained reading provides meaningful opportunities for vocabulary growth. A similarly important relationship exists between vocabulary and speaking. Productive oral communication requires rapid lexical retrieval, appropriate lexical selection, collocation knowledge, discourse-organising expressions, and the ability to adapt language to context. The article further proposes an integrated vocabulary-development cycle—encounter, notice, understand, record, review, retrieve, use, and reuse—as a practical framework for classroom and independent learning. The discussion highlights the importance of moving from receptive recognition towards productive and flexible use without treating vocabulary size as a sufficient measure of communicative competence. The article concludes that vocabulary development is most productive when it is embedded in meaningful reading, interaction, speaking, reflection, and repeated use. For higher education, an integrated approach can strengthen students’ access to academic texts and their ability to communicate ideas with greater clarity, precision, and appropriateness.