Having the quality, character, or nature of a diphthong; composed of or containing diphthongs.
From 'diphthong' + '-ous' (full of/characterized by). This adjective uses the common '-ous' suffix to describe something that has or is full of diphthongal qualities.
English is famously 'diphthongous' compared to languages like Spanish or Italian, which means English speakers naturally make more complex vowel glides with every other word they say!
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