Peter Ladefoged in the context of "University of California, Los Angeles"

In articulatory phonetics, the manner of articulation is the configuration and interaction of the articulators (speech organs such as the tongue, lips, and palate) when making a speech sound. One parameter of manner is stricture, that is, how closely the speech organs approach one another. Others include those involved in the r-like sounds (taps and trills), and the sibilancy of fricatives.

The concept of manner is mainly used in the discussion of consonants, although the movement of the articulators will also greatly alter the resonant properties of the vocal tract, thereby changing the formant structure of speech sounds that is crucial for the identification of vowels. For consonants, the place of articulation and the degree of phonation or voicing are considered separately from manner, as being independent parameters. Homorganic consonants, which have the same place of articulation, may have different manners of articulation. Often nasality and laterality are included in manner, but some phoneticians, such as Peter Ladefoged, consider them to be independent.

A voiced alveolar tap or flap is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents a dental, alveolar, or postalveolar tap or flap is ⟨ɾ⟩.

The terms tap and flap are often used interchangeably. Peter Ladefoged proposed the distinction that a tap strikes its point of contact directly, as a very brief stop, and a flap strikes the point of contact tangentially: "Flaps are most typically made by retracting the tongue tip behind the alveolar ridge and moving it forward so that it strikes the ridge in passing." That distinction between the alveolar tap and flap can be written in the IPA with tap ⟨ɾ⟩ and flap ⟨ɽ⟩, the 'retroflex' symbol being used for the one that starts with the tongue tip curled back behind the alveolar ridge. The distinction is noticeable in the speech of some American English speakers in distinguishing the words "potty" (tap [ɾ]) and "party" (retroflex [ɽ]).

A Course in Phonetics is a textbook by Peter Ladefoged and Keith Allan Johnson designed for an introductory course in phonetics.

The Sounds of the World's Languages, sometimes abbreviated SOWL, is a 1996 book by Peter Ladefoged and Ian Maddieson which documents a global survey of the sound patterns of natural languages. Drawing from the authors' own fieldwork and experiments as well as existing literature, it provides an articulatory and acoustic description of vowels and consonants from more than 300 languages. It is a prominent reference work in the field of phonetics.

Following discussions of the book's aim and underlying frameworks, the description of sounds is divided into chapters on stops, nasals and nasalized consonants, fricatives, laterals, rhotics, clicks, vowels, and multiple articulatory gestures, which are then followed by a discussion of the data's phonological implications.