This chapter presents the processes that have resulted in dialectal fragmentation of Slavic languages. It starts with a discussion of early differences in Proto-Slavic, most notably those in reflexes of palatalizations. It then goes on to discuss the variation before the split of the common Slavic community into three branches. This is followed by the presentation of early East Slavic tribal dialects. Next, early lexical differences across and within Slavic languages are considered. The discussion continues by addressing inter-Slavic areal features and prosodic continua. Finally, external factors of fragmentation are discussed (economic, political), alongisde contacts with non-Slavic languages and sociolinguistic factors.

Vowels are one of two principal types of speech sound, the other being consonants. Vowels are typically produced with voicing, and with a vocal tract open at least as much as it is for the vowel [i]. Vowels are classified by height and frontness/backness, these terms referring to the highest point on the surface of the tongue. This range of space within the oral cavity is called the vowel quadrangle, based on its shape. Other characteristics are also used in the classification of vowels, besides these two principal ones. These include rounding/labialization, tenseness/ATR, nasalization, duration/length, and syllabicity. The group of front unrounded and back rounded vowels comprise what are called cardinal vowels or primary vowels; these are the most common vowels in the world’s languages. Secondary vowels include front rounded and back unrounded vowels. Nasalization of vowels involves opening the velopharyngeal port during their production.

The word consonant means 'with a sonant' or vowel. Consonants are one of two main types of speech sounds, the other being vowels. In the production of consonants, the vocal tract is blocked, the vocal tract is seriously constricted, or the airflow is diverted through the nasal passage. The term articulation is used for the movements and adjustments required to produce an individual speech sound. Consonants are classified by (1) whether the vocal folds are vibrating, (2) where in the vocal tract articulation takes place, and (3) the manner of articulation (the type of articulation). Manners of articulation include plosives, nasals, fricatives, and approximants, the latter of which can be broken down into laterals and glides. Other manners of articulation include trills. Consonants may be produced with a secondary articulation in addition to the primary articulation.

Consonants are speech sounds produced with a closure or near complete constriction of the vocal tract. All languages systematically exploit place of articulation to differentiate consonants. Eight other phonetically independent parameters are used to create consonant contrast: airstream, constriction degree, laryngeal setting, nasality, laterality, length, articulator stiffness, and respiratory strength. Aspiration, affrication, pre-stopping, secondary articulations, and other properties of ‘complex’ consonants are best described as patterns of coordination in the underlying gestures.

Chapter 2 uses a variety of investigative activities to guide readers through an exploration of the sounds and articulations of the world’s languages and the linguistic rules that govern their appearances. It begins with an overview of the acoustic characteristics of speech sounds, which are then employed in a discussion of the articulation apparatus. Throughout, students are directed to engage in their own investigations with the material via the Discover Activities. Various data from a variety of languages are provided to illustrate different phonological rules, and the techniques linguists use to discover them through analysis. These insights are then transferred to a discussion of transformations and processes that complicate phonological systems.

Chapter 2 provides an overview of phonetics, the study of human speech sounds. It examines two main approaches: articulatory phonetics, which shows how humans produce the sounds of language, and acoustic phonetics, which explains the physical properties of speech sounds. The chapter explains how speech is produced by modifying the shape of the vocal tract and how the articulators interact. We learn why the International Phonetic Alphabet is necessary to study world languages, and ample practice in using the IPA is provided. Practice goes hand in hand with a detailed categorization and description of speech sounds, both consonants and vowels, summarized in charts and figures. The chapter also examines speech processes which lead to changes in the quality of a sound due to the linguistic context. Descriptions and examples of processes such as assimilation, palatalization, nasalization, dissimilation, epenthesis, and deletion, are included in this section. The final part of the chapter introduces readers to acoustic properties of speech sounds by focusing on spectrograms and how to interpret them.