 This e-lecture focuses on the main reasons for language change. It is enormously difficult to be precise about these reasons. Apparently, a number of interacting factors are at work when languages change their structure. These factors can be subdivided into external factors and internal factors. External factors are non-linguistic by nature and internal factors relate to the organizational principles of natural languages themselves. Let us start with the external factors. One central factor that is listed here has to do with the geographical organization of languages and their varieties. When people move away from each other, their languages or dialects will diverge. New experiences will be made and at least the vocabularies will change. Well, here is an example from North America. When people want to buy a carbonated drink to quench their thirst, what would they say when they order it? Would they ask for a soda, a pop, a coke or something else? Well, quite interestingly, in the south, roughly this part here, the generic term coke is used because that drink is predominantly used. Pop, by contrast, dominates the north and the northwest. So this is an area where people would order a pop. Well, and in California and in parts of the northeast, people would prefer the term soda. In the past, people were geographically divided by mountain ranges, rivers, oceans, former kingdoms, etc. Today, however, the increased mobility of people within and between countries makes the geographical factor even more important than ever before. A second factor is referred to as social prestige. Now, people come to talk like those they identify with or who they admire. This process may be conscious or subconscious. A conscious change can be observed in those cases where people want to avoid a certain feature in their spoken or written language. William Labov produced a famous example of such a conscious change. Now, here is William Labov, the leading sociolinguists of our time. Now, what he did, he selected three storehouses in New York City and he wanted to find out whether people produce the post-vocalic art in their speech or not. So, do they say something like car, the British variant, or do they prefer car, the today's North American variant? Well, he selected the following storehouses which are different in terms of prestige. So, whereas, S. Klein is relatively low in terms of prestige, Sax is ranked relatively high with Macy's in the middle. Now, what Labov did was brilliant and simple at the same time. He simply asked people where he could find a certain type of trousers, shirt or whatever and they had to answer something like, well, on the second floor. Well, he found out that the results were something like this. In the less prestigious storehouses, people would prefer the variant without a post-vocalic art, so they would prefer floor. Whereas in the prestigious storehouses, the tendency was to use the post-vocalic art. Hence, it was considered to be prestigious by those who bought their clothes in cheap priced stores at the time to sound British. Today, this is no longer the case. Subconscious change is less noticeable but more common. Such changes may be towards a favourite accent or dialect which has high prestige or away from what is considered not to be prestigious. For example, look at British English. Here you see a picture of the Queen. Now, in British English RP, the type of English used by the upper class has a high prestige scientifically but a relatively low prestige among ordinary people. Let's move on with the main internal factors. One of these factors is referred to as ease of articulation. Now, in the 19th century, it was widely believed that sounds change because speakers want to minimise their articulatory effort. On this basis, sounds and sound systems would become simpler over long periods of time. In fact, there is evidence in various types of sound changes that this is the case. Here is an example from Old English. In Old English, we had the following verb, driven, which means to drive in present-day English. Now, phonemically, this can be transcribed like this, driven. Now, what happened? Well, at the first stage, the final alveolar nasal was dropped. The result was driver. And since final or unstressed schwa is often dropped too by means of processes of elision, at a later stage, the result was drive. Well then, at further stages of the development of English, of course, the vowel changed here. The great vowel shift came into action, but that's a different story. In contrast to such obvious cases of the ease of articulation, there are many cases where articulatory complexity is unaffected by a sound change. And there are even cases where the complexity of a sound system has increased. Compare the vocalic systems of Old English, which is relatively simple. With the present-day English sound system of RP, for example, with 20 vowels. So only a small part of language change can be explained by a principle of minimizing the articulatory effort. Other factors must come in. One of such factors is referred to as analogy, which is often discussed together with the principle of reinterpretation. Let's look at analogy and reinterpretation in more detail. Here we have the system of relative pronouns in present-day English. In fact, we have three paradigms. We have the paradigm who, who's, who, which relates to personal nominals. Then which, whose, which relates to impersonals. So let's write down minus personal. Well, and then we have a pattern that, who's that, which can be related to both, plus or minus personal. So in relative clauses, like the boy and then relative pronoun I saw, we can use that in each case. The boy that I saw, the house that I saw. If we relate it to just the personal one, we have to say the boy who I saw and the house which I saw. Now what is happening? Well, in the, that, who's, that paradigm, we have identity between the two forms that signal the object and the subject position. This would be the object position and this would be the subject position. So there's no difference. And the same applies to the paradigm of the minus personal environment. Again, we have no difference between the subject position, which, and the object position, which. However, in this case here, who and whom, we have a difference. And we would have to say the boy whom I saw because here we have an object relative pronoun versus the boy who is my friend, which would be the subject position. Now what is happening in present day English is that by means of an analogical change, these two forms who versus whom are also made identical. In other words, the final bilabian nasal is dropped. And this explains why by analogy, there's a change going on reducing the complexity in the personal paradigm where most native speakers of English would now accept the form the boy who I saw. It should be noted though that analogy does not create new patterns. Rather, it extends the patterns that already exist in the language. Closely related to the process of analogy is the mechanism of reinterpretation, a type of change that primarily applies to changes in syntax. In middle English, for example, we had the so-called impersonal constructions where there was no overt subject. So a form like me dream it with the topic me didn't involve a subject, a subject that in terms of pronouns is normally marked in the nominative case. But me is certainly not a nominative marked pronoun. So there was no subject. However, since the majority of the cases in English involves true subjects, which are either not case marked at all in the case of standard nouns, but can be case marked in terms of some pronouns, I, he, we and they, for example. Now by analogy with this majority of cases, this construction was reinterpreted where me dream it became I dreamed. And now we have a true subject which is marked in the nominative case. So a principle of reinterpretation in syntax. Finally, language change may be the effect of language contact. It is well known that when languages come into contact, they tend to borrow from one another. The most obvious form is the borrowing of lexical items. The history of English is full of examples of such kind. For example, after the Norman conquest, during the early period of Middle English, numerous words from several lexical fields entered the English language fields such as law or government. Here you see just some of the terms that entered the English language during the early days of Middle English. In summary then, language change is due to an interplay of several factors, external and internal ones.