Dipthongs

The word dipthong (also spelt diphthong) comes from the Greek δίφθογγος meaning "with two sounds," or "with two tones".

Try pronouncing these words:

If you listen carefully you’ll find that the first vowel sound in each of these words changes considerably in quality during the pronunciation of the syllable. You'll also notice that the shape of your mouth changes mid-way through the pronunciation of the vowel.

There you have your dipthong! Two vowel sounds in one syllable.

To put it into more appropriate terminology a diphthong is a monosyllabic vowel combination involving a quick but smooth movement from one vowel to another, often interpreted by listeners as a single vowel sound or phoneme.

Dipthongs are thus distinguished from simple vowels (cat, feed, etc.).

The term is sometimes also used to refer to sequences of vowel letters, or diagraphs (conventional two-letter sequences with special values), for example, the ea of bread, pronounced as a single vowel; particularly so when written as a ligature, as æ in Cæsar.

While pure vowels are said to have one target tongue position, dipthongs have two target tongue positions.

Pure vowels or monothongs (also spelt monophthong) are represented in the International Phonetic Alphabet by one symbol.

Dipthongs are represented by two symbols with the two vowel symbols representing approximately the beginning and ending tongue positions.