Orthographic variability is the norm in Old and Middle English: spelling is purely phonetic until about the fifteenth century. Partly under the influence of printers' practices, spelling becomes more stable and "traditional" beginning in the fifteenth century (and many of the peculiarities of the modern English spelling system--the quantities of "silent" letters in words like "knight," for instance--have to do with the fossilization of fifteenth-century spellings), but it is Samuel Johnson's and Noah Webster's dictionaries in the eighteenth and early nineteenth centuries which "fix" British and American spelling systems with their differences and idiosyncracies.
Old English is, relatively, a highly inflected language, with consequent looseness of syntax. One aspect of the history of English through Middle to Modern English is the gradual loss of inflectional endings and the correspondent fixing of syntactic structures into a quite rigid Subject-Verb-Object order.
Punctuation as we know it is an Early Modern development, based upon medieval systems of "pointing" texts.
[ Course Notes: Introduction ] | [ I. Towards a definition of "manuscript studies" ] | [ I.ii. The four branches of bibliographical study ] | [ I.iii. Topics in the social history of texts ] | [ II. Diplomatics ] | [ III. Codicology ] | [ III.ii. Decoration and Illumination ] | [ IV. Paleography ] | [ IV.ii. Historical Notes ] | [ IV.iii. Writing Implements ] | [ IV.iv. Letter Formation ] | [ IV.v. Special Characters in English Manuscripts ] | [ IV.vi. Scribal Abbreviations ] | [ IV.vii. Punctuation ] | [ IV.viii. Paleographical sample: William Herebert, OFM (early fourteenth-century England) ] | [ Herebert sample, with transcription ] | [ Herebert sample: enlargement of full page reproduced at high resolution ] | [ V. Textual analysis (James E. Thorpe) ] | [ V.ii. Scribal error ] | [ V.iii. Kinds of edition ] | [ V.iv. Examples of over emendation on insufficient grounds ] | [ VI. Linguistic competence (an example): An Outline History of the English Language ] | [ VII. Libraries and archives: ] | [ VII.ii. British Library Manuscript Collections ] | [ VII.iii. Bodleian Library Manuscript Collections ]