13 Connecting these points gives us a box called the Vowel Quadrilateral
14 All the vowel sounds that the human voice can produce may be plotted within the limits of the quadrilateral
15 Here is the vowel quadrilateral divided into sectors with the IPA symbols at fixed points. These are called Cardinal Vowels.
16 N.B. Do not confuse symbols for cardinal vowels with language specific phonemes The IPA vowel quadrilateral is a grid on which we can plot vowelsIt indicates the total area in which vowels can be produced by human beings, the cardinal vowels are fixed reference points on this chart, just like lines of longtitude and latitude on a mapPlots of language specific vowels do not usually correspond to the cardinal vowels, e.g. the Italian /a/ does not correspond to the cardinal vowel [a]
17 The four corners of the quadrilateral may be seen as the four corners of a map –
18 Plotting vowels within the chart is like plotting the irregular outlines of topography
19 These are the places of articulation of English short and long pure vowels
20 The chart of Standard Italian vowels would look like this:
21 The fact that Italian lacks vowels in the central area may well explain why Italian students of English have so much trouble with these sounds
22 However, it is important to remember that the cardinal vowel system describes vowels from an articulatory point of view…
23 …whereas vowels are an acoustic phenomenon and may also be described according to their acoustic properties.
24 Plotting the values of the 1st and 2nd formants results in a graph which greatly resembles the quadrilateral
25 We can note that the values of the acoustic properties are not always exactly the same: they tend to vary considerably
26 This type of analysis can be used to illustrate the difference between native (left) and non-native speakers’ production (right)
27 Native (left) and non-native speakers’ production (right)
28 Length English vowels differ in length as well as in quality These differences are as important to perception as qualityEnglish long vowels are far longer than Italian equivalents (e.g. /i:/, /u:/)
29 The distinction between long and short vowels is not always very clear The realisation of long and short vowels depends on their context, this is called ClippingThis means that long vowels and diphthongs tend to be shortened before voiceless consonants e.g. /p/, /t/, /k/, /f/ etc.
30 Vowel length in centiseconds: (Data from Gimson 1980:98)
31 Potential ambiguityItalian speakers of English often produce vowel sounds that can be misinterpreted by native speakersThis is particularly important in the case of minimal pairs i.e. where substituting one vowel sound for another leads to semantic changesThis can be due to the irregular orthography of English or interference from L1. We will now examine this second case.
32 / i: / v. / i /e.g. sheep v. ship. Italian speakers often use one vowel sound, the Italian /i:/ for both. In the case of sheep the vowel length is too short, in that of ship the quality does not exclude ambiguity.
33 Other casese.g. ban and bun – here the problem is one of vowel qualitye.g. coat and court – the Italian /o/ is often used for both