 Hello, I welcome you to an e-lecture about morphological alternation, a subfield within morphology referred to as alomorphy. And I have my friend Pepper with me. Welcome to all of you, I am glad to be here. As you know, morphemes may have different shapes under different circumstances. What are the shape of the indefinite article A in English? Yes, we have a book and a car, then an answer and an idea, and sometimes even strong forms, such as A, A, great, concert. Yes, in other words we have three alomorfs that represent the morpheme A. But how do we know when to use which alomorf? Well, we can define three conditions under which a particular alomorf is selected. Phonological conditioning, where the sound structure conditions the choice of alomorfs. Morphological conditioning, where the morphological context conditions the choice of alomorfs. And lexical conditioning, where the choice of alomorfs depends on a particular lexeme. Let's look at phonological conditioning first. Okay. Consider the following English word pairs. Cat, cats, dog, dogs, and horse, horses. In all three pairs, the plural morpheme S is phonologically different. Sir, sir, and is. However, the distribution of its alomorfs is complementary and can be predicted on the basis of the final stem consonant. In cat, the final phoneme is voiceless. In dog, it is voiced. And in horses, we have a voiceless alveolar fricative at the end. Conditions of this kind can be generalized and can easily be converted into morphological rules. Let us now look at some other languages, for example, at Turkish. Can you speak Turkish, Jürgen? No, Peppa, but as a linguist, I know that the plural morpheme in Turkish has two alomorfs, ler and lar. The occurrence of these alomorfs is clearly phonologically conditioned. Ler occurs if the final stem vowel is a front vowel. And lar has to be chosen if the final stem vowel is a back vowel. Or take Hungarian, another language I do not speak. But I understand you know some of its rules. Yes, I know that the morpheme that denotes the locative relation in has two alomorfs, ben and barn. And the occurrence of these alomorfs is clearly phonologically conditioned. Ben occurs if the final stem vowel is a front vowel. Barn has to be chosen if the final stem vowel is a back vowel. Isn't this some sort of harmony? Yes, the phenomenon where the vowel of an alomorf has to be harmonized with a stem vowel has become known as a vowel harmony. And this is typical for Turkish and Hungarian. Gözler, dudaklar, levegüben, fölben. Let us now continue with morphological conditioning. It occurs if the choice of alomorfs is determined by the morphological context. Take the words chief and thief and room in present-day English and generate the genitive case. Yes, it's chiefs, thieves and rooms. Okay, good. So in the first two cases we have a voiceless labiodental fricative at the end of the base form. And not surprisingly, we take the voiceless alomorf. Room, by contrast, ends in a voiced bilabial nasal. So we add the voiced alomorf. No problem. But what about the plural forms? No problem for chiefs and rooms. But what about thieves? It has a voiced plural form. How do I know? You did it right. Chiefs and rooms are phonologically conditioned not only in their genitive forms but also in their plural forms. But thieves behave differently in a particular morphological context, namely in the plural. This phenomenon, where the choice of an alomorf is determined morphologically, is referred to as morphological conditioning. So the plural of thief is morphologically conditioned. Yes, but there are cases where neither the phonological nor the morphological context can help and where the choice of alomorfs cannot be derived by any rule at all and it has to be learned. This applies to the English past participle affix en, where speakers have to learn which verbs take this suffix. For example, taken, seen, given and so on. Such cases are referred to as lexical conditioning. Here is an example from Persian. Persian. Another language you speak? No, no Peppa. As I said, as a linguist you need not speak many languages but you should understand the principles of as many of them as possible. And I know that Persian plural marking depends on the semantic properties of the base. Human versus non-human, as in these two examples. Merdan and Gorbehar. Clearly another case of lexical conditioning. Shall we summarize? For me it's clear, but please go ahead. As we saw, morphological alternation is a common phenomenon across languages. However, as outlined, several conditions can be postulated that allow us to determine the choice of alomorfs and to set up morphological rules. The discovery of such rules, especially phonological rules as conditions for morphological alternation, is one of the major goals in the morphological analysis of the languages of the world. Okay, I got it. See you again soon. Yes, bye bye from me too.