diphthongen

Diphthongen are vowel sounds that change quality during a single syllable, moving from one vowel to another within the nucleus. The term is the Dutch plural for diphthong and is used in Dutch linguistics to describe these pronounced sequences. A diphthong is typically described as having an on-glide (the starting vowel) and an off-glide (the ending vowel), forming a single phonetic segment rather than two separate vowels.

In phonology, diphthongen contrast with monophthongs, which maintain a constant vowel quality. They can be phonemic, meaning they distinguish words, or arise from the phonotactic rules of a language where two adjacent vowels influence pronunciation as a single unit. Some languages treat certain sequences as single long vowels with a glide, while others analyze them as two vowels in contact.

Orthographically, diphthongen are often written with digraphs or letter clusters (for example, in many languages the sequences represented by ai, ei, au, ou). The spelling does not always map directly to the exact phonetic realization, since pronunciation can vary by dialect and context.

Diphthongen are common across languages, including English and Dutch, and form a significant part of their vowel inventories. In English, examples include those in price (aɪ), house (aʊ), and go (oʊ). The exact set of diphthongen and their phonetic values differ by language and dialect. Some languages also feature triphthongs, longer vowel sequences that move through three distinct qualities within a syllable.

Overall, diphthongen enrich vowel systems by allowing dynamic vowel articulation within a single syllable, contributing to regional and dialectal variation in pronunciation.