Old English syntax and word order differed significantly from Modern English. The language had a complex case system, allowing for more flexible sentence structures. Main clauses often followed a verb-second pattern, while subordinate clauses typically used subject-object-verb order. Understanding Old English syntax involves recognizing various word order patterns, including SVO, SOV, and V2. The case system's impact on word order, differences between prose and poetry, and practical text analysis are crucial aspects of studying Old English sentence structure.