Like other languages, English has changed greatly, albeit imperceptibly, so that an English speaker of 1300 would not have understood the English of 500 nor the English of today. Changes of every sort have taken place concomitantly in the sounds (phonetics), in their distribution (phonemics), and in the grammar (morphology and syntax). The Changes in English Pronunciation table demonstrates how a few familiar words have altered over the span of a thousand years. The changes shown in the table are more radical than they appear, for Modern English ō and ā are diphthongs. The words stones and name exemplify the fate of unaccented vowels, which became ə, then ə disappeared. In Old English important inflectional contrasts depended upon the difference between unaccented vowels; so, as these vowels coalesced into ə and this disappeared, much of the case system disappeared too. In Modern English a different technique, word order (subject + predicate + object), is used to show what a case contrast once did, namely, which is the actor and which the goal of the action.
Although the pronunciation of English has changed greatly since the 15th cent., the spelling of English words has altered very little over the same period. As a result, English spelling is not a reliable guide to the pronunciation of the language.
The vocabulary of English has naturally expanded, but many common modern words are derived from the lexicon of the earliest English; e.g., bread, good, and shower. From words acquired with Latin Christianity come priest, bishop, and others; and from words adopted from Scandinavian settlers come root, egg, take, window, and many more. French words, such as castle, began to come into English shortly before the Norman Conquest. After the Conquest, Norman French became the language of the court and of official life, and it remained so until the end of the 14th cent.
During these 300 or more years English remained the language of the common people, but an increasingly large number of French words found their way into the language, so that when the 14th-century vernacular revival, dominated by Chaucer and Wyclif, restored English to its old place as the speech of all classes, the French element in the English vocabulary was very considerable. To this phase of French influence belong most legal terms (such as judge, jury, tort, and assault ) and words denoting social ranks and institutions (such as duke, baron, peer, countess, and parliament ), together with a great number of other words that cannot be classified readily—e.g., honor, courage, season, manner, study, feeble, and poor. Since nearly all of these French words are ultimately derived from Late Latin, they may be regarded as an indirect influence of the classical languages upon the English vocabulary.
The direct influence of the classical languages began with the Renaissance and has continued ever since; even today Latin and Greek roots are the chief source for English words in science and technology (e.g., conifer, cyclotron, intravenous, isotope, polymeric, and telephone ). During the last 300 years the borrowing of words from foreign languages has continued unchecked, so that now most of the languages of the world are represented to some extent in the vocabulary. English vocabulary has also been greatly expanded by the blending of existing words (e.g., smog from smoke and fog ) and by back-formations (e.g., burgle from burglar ), whereby a segment of an existing word is treated as an affix and dropped, resulting in a new word, usually with a related meaning.