Definition

1. Verb:
   • To change a simple vowel sound into a diphthong (a complex vowel sound that begins with one vowel quality and glides to another within the same syllable).

Usage

• The verb diphthongise (also spelled ) is used in the field of linguistics, specifically phonetics and historical phonology. It describes a phonetic process where a single, pure vowel sound evolves or is articulated as a combination of two vowel sounds.
• It is typically used in an intransitive sense (e.g., "The vowel diphthongised over centuries") or in a passive/descriptive transitive sense (e.g., "The language diphthongised certain vowels").

Examples

• Verb:
  • In many dialects, the long 'i' sound in 'mine' has been diphthongised from a pure vowel to /aɪ/.
  • Linguists note that some vowels tend to diphthongise in unstressed positions.
  • The reference states: "This vowel diphthongized in Germanic."

Advanced Usage

• Causative/Transitive Use: While often intransitive, it can be used transitively to describe the action of causing the change.
  • The Great Vowel Shift effectively diphthongised several Middle English long vowels.
• In Linguistic Description: The term is used to label and analyze sound changes in the history of languages.
  • The process that diphthongised Latin /ɛː/ to Old French /ei/ is well-documented.

Variants and Related Words

• Diphthongize (verb): The preferred spelling in American English.
• Diphthongisation / Diphthongization (noun): The process or result of diphthongising.
  • The diphthongisation of vowels is a common historical sound change.
• Diphthong (noun): The resulting complex vowel sound (e.g., /aɪ/, /oʊ/).
• Monophthongise (verb): The opposite process; to change a diphthong into a simple vowel.

Synonyms

• Glide (in a specific phonetic context): While not a perfect synonym, a vowel can be said to , leading to diphthongisation.
• Vowel break (in historical linguistics): A term for a specific type of diphthongisation where a vowel splits into two elements.

Antonyms

• Monophthongise: To simplify a diphthong into a single, pure vowel sound.
• Stabilise (in a phonetic context): To remain or become a steady, unchanging vowel quality.

Verb

1. change from a simple vowel to a diphthong
   • This vowel diphthongized in Germanic