The lax and tense vowels we have looked at so far are monophthongs, sometimes called pure vowels. This is because the tongue and lips are relatively stationary while these vowels are being pronounced - the vowels do not move around in the vowel chart. Diphthongs, on the other hand, move through the chart as they are pronounced: they start at one vowel-position, and move towards another. The word di-phthong is from Greek: it means "two vowels", and we write them as two vowels.
Diphthongs are tense vowels; they can be unchecked, and are subject to clipping like the "pure" tense vowels - they can be long or short.
It's useful to distinguish between rising and centring diphthongs:
SOME OF THESE PRONUNCIATIONS may not be the ones you're used to. See Notes
CHART POSITIONS OF THE DIPHTHONGS:
Here is a link to a map showing the distribution of the rhotic and non-rhotic accents of English.
Non-rhotic accents such RP and some other types of British English, Australian, New Zealand and South African English, where r does not occur unless a vowel follows. Thus the word 'farmer' is pronounced .
Rhotic accents such as Scottish, Irish, American and Canadian English, and the south-western accents of English, where r can occur without a following vowel. Thus the word 'farmer' is pronounced .
The centring diphthongs occur only in the non-rhotic accents.
In the rhotic accents, words such as NEAR SQUARE and CURE are pronounced with a single vowel (monophthong) followed by r.
This is by far the rarest vowel in RP (with a frequency of 0.06% - see Vowel Frequencies) - and is getting rapidly rarer, since words in the CURE set are moving over to THOUGHT, . This happened decades ago in mainstream RP with words such as 'sure' and 'poor', , , and in newer RP and Estuary English all of the old CURE set have gone over to THOUGHT.
Difference between SQUARE and NEAR
You'll hear different pronunciations of these two vowels (for instance, in some accents the disappears and the remaining vowel lengthens) but most accents of English keep them clearly distinguished. On the other hand speakers of English as a foreign language sometimes confuse these vowels, and Icelanders often do. This means that Icelandic speakers of English have to be particularly careful to distinguish them. Predictably, spelling will not help you much: youhave to use a good pronunciation dictionary. Here are some spelling guidelines:
SQUARE words are spelled 'air' or 'are'
air chair fair - bare care fare
NEAR words are spelled 'eer', 'ier'
beer engineer queer - fierce pier
But words spelled 'ear', 'eir' and 'ere' are variable, and you may have to look them up:
SQUARE: bear pear wear - heir their - there where NEAR: fear rear clear - weir - here
Newer pronunciations of SQUARE and NEAR
The diphthongal pronunciation of SQUARE and NEAR occurs in RP and the South
of England. However, a newer, monophthongal pronunciation is becoming common in
Britain, and is regular in Australia, New Zealand and South Africa: instead of
you will hear lenthened
versions of DRESS and KIT: and
. See further