Transcript Presentazione di PowerPoint

SPEECH
ARTICULATION:
Vowels

David Brett
Vowels may differ in three ways
• Length
• Quality (i.e. the difference between /i:/ and
/u:/
• Oral or nasal production (unlike French,
this does not have a phonemic function in
English)
We will now look at how vowels vary in quality…
These are x-rays of a person producing
different vowels
In the close front position
(unrounded) we produce /i/
In the open front position
(unrounded) we produce /a/
Back open (unrounded) : //
Back close (rounded): /u/
Connecting these points gives us a box called the
Vowel Quadrilateral
All the vowel sounds that the human voice can
produce may be plotted within the limits of the
quadrilateral
While the quadrilateral system is widely used it
remains a hypothesis and is not necessarily the
only possible way of representing vowels
Here is the vowel quadrilateral divided into sectors
with the IPA symbols at fixed points. These are
called Cardinal Vowels.
This is the full set:
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 vowels
• It 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 map
• Plots 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]
The vowels appear in pairs depending on whether
they are articulated with spread lips, (unrounded )
indicated here in green:
Or with rounded lips (red):
Generally, front vowels are
unrounded and back vowels
rounded…
Italian and English follow this
pattern…
…while German and French do not
(v. /y/, // etc.)
These are the places of articulation of English
short and long vowels
The vowel system of Br English
Short
/ɪ/
/e/
/æ/
/ʌ/
/ə/
/ʊ/
/ɒ/
Fish
Bed
Cat
Cut
Mother
Good
Dog
Long
/i:/
/ɔ:/
/ɑ:/
/u:/
/ɜ:/
Week
Door
Car
Food
Nurse
The chart of Standard Italian vowels would look
like this:
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
However, it is important to remember that
the cardinal vowel system describes
vowels from an articulatory point of
view…
…whereas vowels are an acoustic
phenomenon and may also be described
according to their acoustic properties.
Spectrogram of four vowels: /i:/,
//, /:/ and /u:/
Each vowel has a different disposition of
formants (peaks at certain frequencies)
Plotting the values of the 1st and 2nd
formants results in a graph which greatly
resembles the quadrilateral
We can note that the values of the
acoustic properties are not always exactly
the same: they tend to vary considerably
This type of analysis can be used to
illustrate the difference between native (left)
and non-native speakers’ production (right)
Native (left) and non-native speakers’
production (right)
Any questions?