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
Types of rapist sadistic rapist may not survive the attack. For some offenders, the ultimate satisfaction is gained from murdering the victim. According to Shannon M. Barton-Bellessa another type of rapist is the sexual gratification rapist. For this type of rapist the only motivation is obtaining sex. Such an offender may otherwise be lonely and may have difficulty obtaining an outlet for their sexual desires in other ways due to being unsuccessful at courtship. Types of rapist Various researchers have set forth different theories concerning types of rapist. According to Howard Barbaree, a psychologist at Queen's University in Kingston, Ontario, most rapes are