Using Trask and other sources explain some of the changes which have taken place in English Language since the middle ages.

The grammar of English language has changed phenomenally over the past thousands of years and whilst most important changes occurred centuries ago and influenced the standardisation of language, grammatical changes are still occurring within Modern English.
Region varieties of English have developed different grammatical forms, for example, take the sentences “the stylus needs changed” and “the stylus needs changing”; one of these will be more familiar and natural than the other. If you live in the southeast of England, in Scotland or in North America the first form will probably be preferred however if you come from the north or the Midlands of England, or are from the southwest then the latter would be preferred and would appear to be of normal grammatical form.
A more obvious grammatical change is shown in the past of the familiar verb “go”. This verb has an irregular past-tense from “yede” or “yode” however, in the fifteenth century it acquired a new past-tense form “went” which follows the same past tense pattern as the verbs “send/sent” or “spend/spent”.
As previously stated, words in the Old English changed their form far more as what occurs within modern language. So, for example, “the king” is variously “se cyning” or “phone cyning”, depending on its grammatical role. As well as this, the order of words in Old English is sometimes rather different from the modern order. The placement of pronouns such as “me” and “it” has particularly changed, for example “she gave it me/she gave me it”.
In Old English, the language construct “passive” has existed side by side with the language construct “active”, the passive and active can be seen within these two sentences; “Edison invented the electric light” illustrates an active construct as this sentence consists of a subject-verb-object form however the sentence “the electric light was invented by Edison” demonstrates the passive as it uses the form object-verb-subject. Although these two constructs existed side by side, for many centuries the passive was limited to occurring in certain very simple types of sentences. In more complex sentences the passive could not be used; this was particularly so with the –ing form of the verb. For example, “I guessed there was some mischief contriving” demonstrates the use of the active construct within language; in modern English this would be seen as unusual grammar. The use of the passive English construct is regularly seen in newspaper articles for titles and subtitles; the passive can easily be misconstrued so journalists will use this in order to make things appear differently to what they actually are.