Vocal tract in the context of "Consonants"

The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling. The human voice is specifically a part of human sound production in which the vocal folds (vocal cords) are the primary sound source. (Other sound production mechanisms produced from the same general area of the body involve the production of unvoiced consonants, clicks, whistling and whispering.)

Generally speaking, the mechanism for generating the human voice can be subdivided into three parts; the lungs, the vocal folds within the larynx (voice box), and the articulators. The lungs, the "pump" must produce adequate airflow and air pressure to vibrate vocal folds. The vocal folds (vocal cords) then vibrate to use airflow from the lungs to create audible pulses that form the laryngeal sound source. The muscles of the larynx adjust the length and tension of the vocal folds to 'fine-tune' pitch and tone. The articulators (the parts of the vocal tract above the larynx consisting of tongue, palate, cheek, lips, etc.) articulate and filter the sound emanating from the larynx and to some degree can interact with the laryngeal airflow to strengthen or weaken it as a sound source.

In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract, except for [h], which is pronounced without any stricture in the vocal tract. Examples are [p] and [b], pronounced with the lips; [t] and [d], pronounced with the front of the tongue; [k] and [g], pronounced with the back of the tongue; [h], pronounced throughout the vocal tract; [f], [v], [s], and [z] pronounced by forcing air through a narrow channel (fricatives); and [m] and [n], which have air flowing through the nose (nasals). Most consonants are pulmonic, using air pressure from the lungs to generate a sound. Very few natural languages are non-pulmonic, making use of ejectives, implosives, and clicks. Contrasting with consonants are vowels.

Since the number of speech sounds in the world's languages is much greater than the number of letters in any one alphabet, linguists have devised systems such as the International Phonetic Alphabet (IPA) to assign a unique and unambiguous symbol to each attested consonant. The English alphabet has fewer consonant letters than the English language has consonant sounds, so digraphs like ⟨ch⟩, ⟨sh⟩, ⟨th⟩, and ⟨ng⟩ are used to extend the alphabet, though some letters and digraphs represent more than one consonant. For example, the sound spelled ⟨th⟩ in "this" is a different consonant from the ⟨th⟩ sound in "thin". (In the IPA, these are [ð] and [θ], respectively.)

A vowel is a speech sound pronounced without any stricture in the vocal tract. Vowels are one of the two principal classes of speech sounds, the other being the consonant. Vowels vary in quality, loudness, and length. They are usually voiced and are closely involved in prosodic variation such as tone, intonation and stress. The nucleus, or "center", of a syllable typically consists of a vowel sound (though this is not always the case).

The word vowel comes from the Latin word vocalis, meaning "vocal" (i.e. relating to the voice). In English, the word vowel is commonly used to refer both to vowel sounds and to the written symbols that represent them: ⟨a⟩, ⟨e⟩, ⟨i⟩, ⟨o⟩, ⟨u⟩, and sometimes ⟨y⟩, and ⟨w⟩.

Real-time magnetic resonance imaging (RT-MRI) refers to the continuous monitoring of moving objects in real time. Traditionally, real-time MRI was possible only with low image quality or low temporal resolution. An iterative reconstruction algorithm removed limitations. Radial FLASH MRI (real-time) yields a temporal resolution of 20 to 30 milliseconds for images with an in-plane resolution of 1.5 to 2.0 mm. Real-time MRI adds information about diseases of the joints and the heart. In many cases MRI examinations become easier and more comfortable for patients, especially for the patients who cannot calm their breathing or who have arrhythmia.

Balanced steady-state free precession (bSSFP) imaging gives better image contrast between the blood pool and myocardium than FLASH MRI, at the cost of severe banding artifact when B0 inhomogeneity is strong.

In articulatory phonetics, the place of articulation (also point of articulation) of a consonant is an approximate location along the vocal tract where its production occurs. It is a point where a constriction is made between an active and a passive articulator. Active articulators are organs capable of voluntary movement which create the constriction, while passive articulators are so called because they are normally fixed and are the parts with which an active articulator makes contact. Along with the manner of articulation and phonation, the place of articulation gives the consonant its distinctive sound.

Since vowels are produced with an open vocal tract, the point where their production occurs cannot be easily determined. Therefore, they are not described in terms of a place of articulation but by the relative positions in vowel space. This is mostly dependent on their formant frequencies and less on the specific tongue position and lip rounding.

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.

The field of articulatory phonetics is a subfield of phonetics that studies articulation and ways that humans produce speech. Articulatory phoneticians explain how humans produce speech sounds via the interaction of different physiological structures. Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.