• Developmental trajectories in language learning reveal age- and sequence-related patterns across first and second language development, including optimal windows, varying attainment, and natural sequences across domains [9], [10], [11], [13], [20].

• Cognitive and theoretical foundations underpin language learning, tracing from Thought and Language to emergent grammars and biological bases of language, suggesting cognitive structure, function, and neurolinguistic constraints shape acquisition [3], [4], [6], [12], [17].

• Bilingualism and cross-language cognition frame language learning as a context for development and transfer, with bilingual experience linked to cognitive patterns, intelligence relations, and cross-domain implications [2], [5], [16], [19].

• Motivation, affective and social dimensions strongly influence language learning, with motivational variables, affective-cognitive-social factors, and classroom psychology shaping persistence, strategy use, and attainment [2], [15], [17], [18].

• Pedagogy and learner strategies emerge as core elements of language education, including syntax instruction, error-based strategies, and frontiers in second-language pedagogy [1], [7], [8], [14], [16].