Long Vowels

· [ỹ] changed to [ī];

· [ǽ] fell together with [έ];

· [ā] changed to [ō] e.g. OE st ā n – ME sto[o:]ne(stone).

As a result:

	close	open
ī	ū	ē	ō	έ	ǿ

New Diphthongs

OE diphthongs turned into monophthongs:

OE Diphth.	ME Sounds	OE	ME
ĭě/īē à	i	l īe htan	l i ghten (lighten)
ĕŏ/ēō à	e	h eo rte	h e rte (heart)
ĕă/ēā à	æ	ēa st	ee st (east)

New diphthongs appeared due to vocalisation of [j], [γ] and [w]. These consonants turned into vowels ([i], [u] and [u] respectively) and became the glides of the new diphthongs:

i-glides	OE	ME	u-glides	OE	ME
[ei]	weζ [j ]	wey [i ] (way)	[iu]	-	-
[ai]	m æ ζ [j]	may [i ] (may)	[au]	la ζ[ γ ] u	law [u] e [‘lauə] (low)
[oi](in French loan-words)		boy, toy	[ou]	cnāw [w] an	know [u] en [‘knouən] (know)

New English

Great Vowel Shift – the change that happened in the 14^th – 16^th c. and affected all long monophthongs + diphthong [au]. As a result these vowels were:

· diphthongized;

· narrowed (became more closed);

· both diphthongized and narrowed.

ME Sounds	NE Sounds	ME	NE
[i:] à	[ai]	time [‘ti:mə]	time [teim]
[e:] à	[i:]	kepen [‘ke:pən]	keep [ki:p]
[a:] à	[ei]	maken [‘ma:kən]	make [meik]
[o:] à à	[ou] [u:]	stone [‘sto:nə] moon [mo:n]	stone [stoun] moon [mu:n]
[u:] à	[au]	mous [mu:s]	mouse [maus]
[au] à	[o:]	cause [‘kauzə]	cause [ko:z]

This shift was not followed by spelling changes, i.e. it was not reflected in written form. Thus the Great Vowel Shift explains many modern rules of reading.