Final answer:
Vocoids and contoids are phonetic terms for vowel sounds with no significant airflow constriction and consonant sounds involving some degree of constriction in the vocal tract, respectively.
Step-by-step explanation:
Vocoids and contoids are terms used in phonetics, which is the study of the sounds of human speech. A vocoid is a speech sound that is produced without any significant constriction or blockage of airflow in the vocal tract, commonly referred to as a vowel sound. Contoids, on the other hand, are speech sounds that involve some degree of constriction or closure at one or more points along the vocal tract, commonly known as consonants. The critical difference between the two is the degree of constriction; vocoids have an open vocal tract configuration, while contoids have a constricted one.