Vowel whose quality does not change over the duration of the vowel is called a monophthong. Monophthongs are sometimes called "pure" or "stable" vowels. A vowel sound that glides from one quality to another is called a diphthong, and a vowel sound that glides successively through three qualities is a triphthong. All languages have monophthongs and many languages have diphthongs, but triphthongs or vowel sounds with even more target qualities are relatively rare cross-linguistically. English has all three types: the vowel sound in "hit" is a monophthong , the vowel sound in "boy" is in most dialects a diphthong , and
Brain types from Jung/Myers) which he believes is more precise: EA, EI, CA, and CI. EA, or 'Empirical-Animate' types (FEAL, FEAR, BEAL, BEAR), are said to excel in the region of the brain responsible for gross motor skills. EI, or 'Empirical-Inanimate' types (FEIL, FEIR, BEIL, BEIR) are thought to possess the best fine motor skills of the four groups. CA, or 'Conceptual-Animate' types (FCAL, FCAR, BCAL, BCAR), excel in the auditory cortex, which is responsible for controlling the mouth and various hearing/language skills. CI, or 'Conceptual-Inanimate' types (FCIL, FCIR, BCIL, BCIR), are believed to excel in the cerebral cortex, where abstract levels