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 e-commerce Types of e-commerce Various types of e-commerce platforms fall into several industry classifications based upon their licensing model, sales scenario and data exchange. On-premises e-commerce software usually requires initial one time purchase investment in terms of licensing fees. Also, it implies extra costs related to hardware and installation services as well as data migration and on-going maintenance fees that are usually charged on a yearly basis for software updates and support. Advantages: Disadvantages: Software as a Service (SaaS)- is a cloud based delivery model in which applications are hosted and managed in a service provider's data center, paid for on