Which of the following terms refers to a combination of two vowel sounds?

The term that describes a combination of two vowel sounds is "diphthongs." Diphthongs occur when one vowel sound glides into another within the same syllable, creating a smooth transition between the two sounds. For example, in the English word "coin," the vowel sound begins as an "o" and glides into a "i" sound, forming a single, complex vowel sound.

This concept is important in phonetics and phonology, as it helps to illustrate how vowel sounds can blend together in speech. Understanding diphthongs is essential for reading specialists because it aids in teaching pronunciation and phonemic awareness, which are critical skills for reading development.

Diphthongs are contrasted with monophthongs, which are single vowel sounds that do not change in quality. Consonants, on the other hand, represent speech sounds produced with a complete or partial closure of the vocal tract, and syllables are units of sound that typically contain a vowel sound along with possibly one or more consonant sounds, rather than focusing on the combination of vowel sounds themselves.