Some recent scientific studies in the field of linguistics and philology increasingly suggest that English cannot be considered a completely homogeneous system.Moreover, its main national varieties -British, American, Canadian and Australian -are characterised by stable and systematic differences at the grammatical, morphological and syntactic levels.This article examines the regional patterns of English usage.The article synthesizes the main structural differences and trends in grammatical development, demonstrating that these variations constitute distinct norms of usage that are crucial for accurate interpretation and translation.Numerous scholars have conducted scientific research on the patterns of English language integration from various analytical perspectives, focusing on features that are particularly important for contemporary descriptive and comparative grammatical studies in specific regional contexts.In particular, scholars from Great Britain have often set standards for English grammar, and contemporary works are usually descriptive, drawing heavily on corpus linguistics.This article focuses on a comparative analysis of grammatical differences between the four main national varieties of English: British English (BrE), American English (AmE), Canadian English (CanE) and Australian English (AusE) through the prism of practical application.It focuses on key aspects of grammatical variation, including tense and case preferences, collective noun agreement, irregular verb morphology, modal and auxiliary verb usage, and fixed prepositional constructions.Drawing on descriptive grammar and corpus research, the article argues that these differences are neither accidental nor stylistic anomalies, but reflect deeper historical, functional, and sociolinguistic processes shaping modern English.The article also discusses the practical implications of grammatical variation for translators and interpreters, emphasising the need for grammatical localization alongside lexical choice.