Understanding Diphthongisation in Language Evolution

Diphthongisation is a process in which a vowel sound changes into a diphthong, which is a combination of two vowel sounds pronounced together. This can occur in various ways, such as when a long vowel sound is pronounced with a following short vowel sound, or when two vowel sounds are combined to form a new diphthong.

For example, in the word "bought", the "ou" combination is a diphthongised form of the vowels /o/ and /u/. Similarly, in the word "coast", the "oi" combination is a diphthongised form of the vowels /o/ and /i/.

Diphthongisation can also occur in the pronunciation of words that have undergone changes in their spelling or pronunciation over time. For example, the word "knight" was originally pronounced with a diphthongised vowel sound in the middle, but this has been lost in modern English.

Overall, diphthongisation is an important process in the evolution of languages, as it can lead to the creation of new sounds and words, and can also help to distinguish one language from another.