The organs of speech refer to the various parts of the human body producing speech sounds. These organs work together to manipulate airflow and create the sounds that form language.
The Lungs
The lungs are crucial for the production of speech. They act as bellows and are located in the chest cavity. Lungs are responsible for providing the airflow needed for sound production. When we speak, air is expelled from the lungs and travels through the trachea. By controlling their breath, speakers can modulate the loudness and pitch of their speech, as well as the rhythm and phrasing. For example, taking a deep breath allows longer sentences or phrases, while a shallow breath might only qualify for shorter utterances.
The Trachea
The trachea, or windpipe, is the tube that connects the larynx to the bronchi of the lungs. It provides a path for air to move in and out of the lungs during breathing. While the trachea itself doesn’t directly contribute to speech articulation, it plays a vital role in the overall vocalisation process.
The Larynx (Voice Box)
The larynx or voice box is a rigid casing at the top of the trachea. It contains a valve-like membranous tissue called the vocal cords, essential for producing voiced sounds. The larynx muscles control the vocal cords’ tension, affecting the pitch and tone of the voice. The vocal cords vibrate to modulate airflow from the lungs to produce a range of pitches and volumes. If the vocal cord vibrates during the production of the sound, it is called a voiced sound, for example,/b/, /d/, /g/. If the vocal cords do not vibrate, the sound is called voiceless, for example,/p/, /t/, /k/.
The Glottis
The glottis is part of the vocal apparatus found within the larynx. It refers to the space between the vocal cords. It’s crucial for speech and language because when the vocal cords tighten, the glottis closes, and when the vocal cords relax, the glottis opens. This opening and closing is vital for producing various speech sounds, most notably the voiced and voiceless sounds in language.
The Epiglottis
The epiglottis is a leaf-shaped flap of cartilage located at the base of the tongue, at the top of the larynx. Its primary function is to seal off the windpipe during eating so that food or liquid does not enter the lungs. It plays a crucial role in swallowing, ensuring that the passage to the lungs is closed off when we swallow and reopens to allow breathing. While the epiglottis is not directly involved in speech production, it does prevent choking or suffocating, which could interfere with the ability to speak.
The Pharynx
The pharynx is the passage that goes from the back of the mouth to the place where it bifurcates for food and air. In the pharynx, the air can undergo modifications owing to the operation of the soft palate. It plays a role in shaping the oral and nasal cavities, affecting the resonance of speech sounds. This resonating cavity aids in producing voiced sounds.
The Hard Palate
The hard palate is the front, bony part of the roof of the mouth. It separates the oral cavity from the nasal cavity. The tongue comes into contact with this to produce certain sounds. The hard palate is crucial in speech, particularly in creating pressure consonants like /p/ or /b/.
The Soft Palate (Velum)
The soft palate or velum is the soft part of the roof of the mouth which lies beyond the hard palate. It acts like a valve, either opening or closing the oral passage of the air. The soft palate can be raised or lowered to control whether air flows through the oral or nasal cavity. It moves to open the nasal passage for nasal sounds or close it for oral sounds. This is crucial for differentiating between oral and nasal sounds.
The Mouth
The mouth is the most important organ involved in the production of speech. The organs in the mouth are divided into active and passive articulators. The lower lip and the tongue are active articulators, while the upper lips, upper teeth, the mouth roof, and the throat’s back wall form the passive articulators.
The Tongue
The tongue is the most flexible organ in the mouth. It can touch various parts of the mouth to create different speech sounds. The tongue has four parts -the tip, the blade, the front and the back. Various sounds are formed when these tongue parts contact the passive articulators.
The Lips
The lips constitute the final outlet of the mouth cavity. The shape the lips assume affects the sound. They may be shut or held apart in various ways. They form a complete obstruction when tightly closed, preventing the air from escaping momentarily. The movements of the lips are essential for producing specific sounds, especially consonants like /p/, /b/, /m/ and /f/.
The Teeth
Teeth play an essential role in speech production, particularly in articulating certain speech sounds called dental consonants. These are sounds produced by placing the tongue against the upper teeth, such as the /θ/ sound in “think”. In addition to their role in articulation, the teeth also maintain the structural integrity of the oral cavity, influencing the resonance and overall quality of all speech sounds. The absence or malformation of teeth can affect speech clarity, demonstrating their importance in proper speech production.
Alveolar Ridge
The alveolar ridge is the bony ridge just behind the upper front teeth. It plays a role in articulating certain speech sounds, particularly alveolar consonants like /t/ and /d/. It is critical in producing several speech sounds, known as alveolar consonants. These include the sounds produced when the tongue tip or blade comes into contact with the alveolar ridge, such as the English sounds /t/, /d/, /n/, /s/, and /z/. This contact’s precise location and nature can vary, leading to different types of alveolar sounds.
These organs contribute to speech production, enabling us to form various sounds in human languages. The lungs provide the air needed to vibrate the vocal cords; the larynx produces the basic sound, and the pharynx, soft palate, hard palate, alveolar ridge, teeth, lips, and tongue all help shape and modify the sound. The study of these organs and their functions is known as articulatory phonetics. Understanding the role of each organ helps explain how speech sounds are formed and how different languages utilise these sounds for communication.