Diphthongisation refers to the process of merging two vowel sounds together to create one sound. There are several synonyms for diphthongisation such as vowel blending, glide formation, and vowel coalescence. All of these terms refer to the same process of combining two distinct vowel sounds into a single sound. Diphthongisation is a common feature of many languages, particularly in English, where it is often used to create a specific sound or accent. Understanding the different terms used to describe the process of diphthongisation can help linguists, language learners, and teachers more effectively communicate about this important linguistic concept.