Park, Sang-soo. 1996. The Effect of Formal Features on the Word Order Change in the History of English. Studies in Modern Grammatical Theories 9: 27-55. According to the descriptive study of texts of OE, the underlying word order of Late OE should be analyzed as a double base hypothesis. We therefore propose that the functional category of IP had both I-final SOVI and I-initial SIOV and the lexical category of VP had head-initial OV in the OE underlying structure. In the Minimalist Program the operation Attract-F is driven by the morphological considerations: the requirement that some formal features must be attracted to the functional category and checked off before Spell-out. We can explain the verb-seconding and the topicalization of OE main clauses using the operation Attract-F. The strong features of [+finite] and [+topicJ appear in the C of CP and attract the morphological features of lexical category to check the verb-seconding in the C and the topicalization in the Spec of CP. The change of underlying word order from SOVI and SIOV of OE to SIVO of ME was triggered by the inflections which were rich and full in the OE period but became reduced and levelled in the ME period The levelled inflections of ME provided the morpho-syntactic motivation for the reanalysis of underlying word order that caused the [+finite] feature in C to incorporate into the (+tense] feature in I and made the verb-seconding and the cliticization disappear in the ME period.