Chapter 4 focuses on morphology, the study of how words are formed. It explains how words, in spite of the fact that we often think of them as a single unit, can be made up of one or more smaller units referred to as morphemes. It examines different types of morphemes: roots, bases, and affixes. It shows how morphemes can be subdivided into different classes according to their properties: whether they are free, stand-alone morphemes, or bound morphemes (affixes), that must be attached to another morpheme; whether they are suffixes, prefixes, or infixes. The concept of allomorphy, important because it represents an interface between phonology and morphology, is presented and practiced. The chapter shows how different languages can build words in different ways, and how in some languages, a word can translate as a whole sentence in English. Readers will learn that morphemes are put together in words following rules, that is, words have structure. Extensive practice is given on how to represent the structure of words using tree diagrams. Various processes for creating or adapting words are also presented. Finally, an appendix details step-by-step how to build morphological trees.

Chapter 3 first summarizes the differences between phonetics (Chapter 2), which looks at human speech sounds in general, and phonology, which examines how a subset of possible sounds is used and distributed in specific languages. It introduces the concept of the phonological unit, the phoneme, and how phonemes can be identified by minimal pairs, that is, comparing words that differ by only one sound yet have distinct meanings. It also explains the difference between phonemes and allophones that are typically the result of sound processes, as seen in Chapter 2, but may also be in free variation. We then explain how phonemes can be reduced to a limited set of distinctive features that allow us to organize them into natural classes to which phonological rules may be applied. We see how these rules can be represented easily to capture important generalizations about phonology. The chapter also examines the structure of syllables and explains how different languages may syllabify words and phrases in different ways, while at the same time obeying universal principles. The chapter ends with a section on how to discover the sound system of a language.

Chapter 1 presents key concepts that are not only of general interest but are useful in understanding subsequent chapters. Although many people place linguistics as foundational for the humanities, we show that it is also a science that develops theories and hypotheses that are rigorously tested. As is typical in scientific inquiry, linguistics seeks to describe and explain an object of study, in our case, language. The chapter also examines how human language differs from other systems of communication, such as animal cries or some visual images. An important component of the chapter distinguishes two main approaches to the study of language: the generativist approach according to which language is constrained by universal principles that are innate, and a more functionalist approach that considers language to be acquired solely on the basis of input. For both functionalist and generativists, input is essential to acquisition. These approaches can be seen in action throughout the book and both are equally important to the field of linguistics. The chapter ends by pointing to different fields that engage with professional linguists, from translation studies to computer science.

Chapter 5 examines syntax, how sentences and phrases are built. It explores the relation between structure and meaning, showing how structure allows us to clarify ambiguity. Readers see how sentences are made up of phrases that in turn are made up of different words. These words belong to specific categories, with the category of the phrase determined by its head. The chapter explains the distinction between lexical and functional categories and presents the two basic processes for building sentences: Merge and move. Readers explore and practice the representation of sentence structure with tree diagrams. They are presented with a template for the representation of structure and shown how to use trees to indicate the difference between complements and adjuncts, and how the tree must represent not only word order but also how different phrases relate to each other. Tense is presented as the head of the sentence, with the verb phrase as its complement. In a parallel fashion, the determiner is presented as the head of the determiner phrase, with the noun phrase as its complement. Different structures such as questions, passives, and relative clauses are introduced and practiced. An appendix details step-by-step how to build syntactic trees.