How Long is an English Vowel Sound?
Here’s a moment most students and teachers of English pronunciation will be familiar with:
Well, let’s test that answer: you are now going to hear 6 words, each one will either be SHIP or SHEEP, all you need to do is decide which one you hear. Ready?
1. 2. 3. 4. 5. 6.
So the /ɪ/ vowel sound in SHIP is not necessarily shorter than the /iː/ vowel in SHEEP, this is not then the main difference between them. The key difference is the lower position of the jaw and more central position of the tongue in /ɪ/; the position of the mouth is always different.
In a normal, (citation) context, in which no special intonation is added to the words, it is true that SHEEP will generally be a tiny bit longer than SHIP, but I really mean a tiny bit – a few milliseconds. OK, let’s have a go everyone: SHIP, SHEEP.
‘LONG’ vs ‘SHORT’ Vowel Sounds
Generally speaking, some vowel sounds tend to be longer than others, but no vowel sound has a fixed length and many other factors affect length, as we are about to see. English contains 6 single (monophthong) vowel sounds that are normally short(ish):
/ɪ/ in PIT
/ʊ/ in PUT
/e/ in PET
/ʌ/ in PUN
/æ/ in PAT
/ɒ/ in POT
5 monophthong vowels that are normally a bit longer
/iː/ in FEET
/uː/ in FOOD
/ɜː/ in FIRST
/ɔː/ in FOUGHT
/ɑː/ in FARM
and 7 double position long vowels (diphthongs) which are normally slightly longer still:
/eɪ/ in FAME,
/aɪ/ in FINE
/ɔɪ/ in FOIL
/əʊ/ in FOAM
/aʊ/ in FOUND
/ɪə/ in FEAR
/eə/ in FAIR
Each of these sounds will change length in connected speech, for three main reasons, as we will now see:
The consonant sound directly after a vowel sound will affect its length. Listen to the different lengths of the sounds /ɪ/ and /iː/ from longest to shortest:
Most noticeably, whenever a voiceless consonant sound /p,t,k,f,s,θ,ʃ,h,tʃ/ comes after a vowel, it makes its length shorter. So compare CARD with CART, BEAN with BEAT and NO with NOTE and you will notice that the second word in each pair was shorter. This means that the supposedly ‘long’ vowel in PEACE is actually normally shorter than the ‘short’ vowel in HID even though you will see them transcribed as /piːs/ and /hɪd/ in dictionaries.
LOSE vs LOOSE
One peculiar pair of words that can confuse learners for this reason, is LOSE and LOOSE. The /uː/ in LOSE /luːz/ is in fact longer that the same sound in LOOSE /luːs/, as the first word ends in a voiced consonant /z/ and the second in a voiceless /s/. The extra vowel in LOOSE has no effect at all on length other than perhaps to confuse learners.
Listen to the following three words, paying attention to the length of the first syllable /kɑː/ in each case:
Notice that /kɑː/ was progressively shorter in each word? This is because the weak vowels after the stressed syllable eat into the space available for the ‘long vowel’. In connected speech, this causes long vowels to reduce in length significantly.
The main stress in a unit of speech will often be longer than normal, compare the length of the word YES /jes/ in this example:
Yes I think I ↘will.
The last syllable in a unit of speech with a fall-rise pattern will also be noticeably longer:
Can we ↘↗go?
How to Learn Vowel Length.
It may help for newcomers to English pronunciation to divide vowels into SHORT, LONG and DIPHTHONG sounds to begin with, simply to learn the range of 19 sounds. It is essential from the beginning, however, to learn the sounds as unique positions of the mouth using the jaw, tongue and lips.
Once the range and position of the sounds is established, their length should be studied in relation to the three factors covered in this article: voicing, reduction, and intonation. So to go back to the original question about the difference between the pronunciation of SHIP and SHEEP, the full answer would be something like this:
“The mouth position is different, with a more open jaw and central tongue position for SHIP, and SHEEP is generally a tiny bit longer.”
To which the teacher should reply: