Language is a dynamic entity, and its change over time is natural. Through the natural change processes, a new variety of language may develop or, if the changes are great enough, an entirely new language may be created.

We have just seen that English has undergone major change through its history. The changes to English resulting from the Norman invasion effectively created a new language, Middle English, and rendered Old English a foreign language to native speakers of English. The changes wrought by the Great Vowel Shift are almost as substantial, but Middle English remains accessible to literate native speakers of Modern English. Nevertheless, the variety of English referred to as Middle English continues to be come increasingly different from the Modern English in use today because the processes of language change continue to function today. Perhaps one day soon we will declare a new period of English has begun.

We will now take a look at both the causes of language change and the processes that drive of language change. We will look back at the three periods of English for examples of the both the causes and the processes.

Causes of Language Change

Contact with Other Languages, Dialects and Cultures

We noted that the Norman invasion in 1066 provided the basis for the break from Old English to Middle English. The changes that occurred as a result of this event happened because two different groups of people began living side by side. The rulers were French-speaking Normans, and the subjects were the English-speaking inhabitants of Britain.

Major changes within the language resulted, but if we look closely, we can see the details of those changes, and we can recognize that such changes always happen in a language when two different peoples and cultures begin to interact. The development of an entirely new language is an extreme result, but the smaller scale changes are very common. The small changes represent the processes by which the larger changes happen.

When two groups of people meet, they swap a variety of things: new concepts, new tools and technologies, new words for the same ideas, and new words for similar, but slightly different ideas, new speech sounds, and new sentence patterns

1. Introduction of new concepts, new items that expand vocabulary through both words and word parts. Examples:
   • sushi has now entered the English language from Japanese as a word for a food dish that was generally unknown until the 1980s
   • siesta entered English from Spanish as a word for a culturally based time of relaxation at midday
   
   
2. Introduction of alternative words and morphemes for similar items that expand vocabulary. For example, both French and English had words for animals and the meat they produced. In Middle English, the French word became the word for the meat, and the English word became the word for the animal. So now we say that we raise cows and eat beef. Examples:
   • French: beef, English: cow
   • French: poultry, English: chicken
   • French: pork, English: pig
   
   
3. Introduction of new words for similar items that replace existing words. Sometimes a word from another language completely replaces the original word in a language. Example:
   • Egg from Old Norse replaced ey in Old English
   
   
4. Introduction of new sound segments that can be incorporated into an existing sound system. Example:
   • [ɜ] voiced alveopalatal fricative (azure, leisure) entered English from French
   
   
5. Introduction of new syntactic patterns Example:
   • In Old English, word order was not as fixed as it is now. Instead meaning depended on word endings (case for nouns and conjugation for verbs).
   • Middle English shows a loss of many endings and introduction of fixed word order. It is possible that endings were lost because they weren't easy for the French speakers to learn.
   
   

1. Addition of vocabulary to name and describe new items. Examples:
   • Television
   • Mouse pad
   
   
2. Loss/Elimination of words that refer to old tools/items. Examples:
   • Surrey
   • Scullery

1. Sound segments are altered, added, or deleted to make a word easier to pronounce. Examples:
   • In Middle English knight [knixt] both the initial k and the palatal fricative represented by gh were pronounced
   • In Modern English both the [k] and the [x] have been deleted.
   
   

1. Analogy: irregular patterns are altered to become more regular. Examples:
   • I had went may be used in place of I had gone. Native speakers who do this are using the rule of regular verbs and applying it to irregular verbs. To them, it doesn't make sense to have two different categories of verbs. This alteration is not accepted as Standard American English, but many native speakers say it.
   
   
2. Reanalysis: an analysis of a structure or morphology that is based on analogy rather than historical forms – especially apparent in morphology. Examples:
   • Herstory is a word that has been added to English recently as an alternative to history. In this case, the first three letters of the word history have been reanalyzed as the masculine pronoun his, and those who use herstory want to make clear that they are discussing women's issues, not men's, and they alter the beginning to her in order to feminize the word. In truth, the first three letters ofhistoryare only coincidentally the same as the masculine pronoun, but the thought processes of speakers have led to the reanalysis.

1. Older pronunciations are retained due to spelling or are reintroduced after being lost. Example:
   • In the word often has the letter t because at one point it was pronounced, and then it was lost, and now is it sometimes reintroduced. American English speakers no longer normally pronounce the [t], but have retained the letter t in the spelling and may pronounce it for emphasis.

When a language changes, a change can occur in a small way, affecting just one word or a few words, or the change can insinuate itself into the whole language as systemic change. The term diffusion refers to the spread of a change throughout the whole language system. A change begins with an effect on a few words and then gradually spreads throughout the language,affecting more and more similar items in the language. Eventually, the changes slow and come to an end, whether all similar items have been affected or not. This is how exceptions typically arise in a language.

One item in American English that is currently undergoing change are some of the vowels. The back mid rounded vowel [ɔ], as in bought and dawn is shifting in the Northern United States as part of the Northern Cities Vowel Shift. In some words it is transforming raising into [o] and in others it is lowering to [a]. This shift has largely occurred already in the Upper Midwest, including Minnesota. What makes the difference on whether it shifts up or down? The other sounds next to it. If the sound is followed by a rounded sound, it will shift up to [o], a rounded vowel. If it is followed by an unrounded vowel, it will lower to [a], an unrounded vowel. Thus, all the [ɔ] sounds are changing. The [ɔ] sounds that are deemed similar are defined by what comes after the vowel.

Thus, to a person from the Midwest, caught [kɔt] and cot [kat]are homophones.Don [dan] and Dawn [dɔn]are also homophones, but bore [bɔr] would never be described as sharing a vowel with bar [bar] but rather as sharing a vowel with boat [bot]. It is unlikely that every English word with [ɔ] in it will shift, however.

To be systemic, not only must a change affect all or almost all instances of a phenomenon, but it must also affect all or almost all of the speakers of the language. That is, the change must spread throughout the population of users of the language. Right now, the Northern Cities Vowel shift has affected many instrnaces of the vowel [ɔ], but it hasn't spread far and wide through the population of American English speakers yet. It has been identified as covering the Northern Cities from Albany and Buffalo, New York, through the Midwest and over into the Dakotas. It has also spread south to St. Louis. This means there are large sections of the U.S. that haven't been affected yet. Also, it has been noted that the shift is occurring in White middle class speakers, and hasn't spread to other ethnic groups.

Once an element of change has entered a language, the language can become more similar to the language of another group of speakers.

Pidgins and creoles are thorough mixes of two languages, but one language provides the base structure.

If Middle English is a creole of English and French, then English is the base, but the changes to English caused by the contact with French-speaking nobility made Middle English closer to French, Latin, nd other romance languages than Old English had ever been.

Other ways a language can become more similar are less massive in scale, but present nonetheless:

• Borrowings of vocabulary: morphemes and words
• Borrowings of sound segments
• Borrowings of sound combinations