Hey everyone thanks for joining us. Welcome!
So today we'll be talking more about 
articulatory phonetics, 
which again is the study of the production
of speech sounds in the vocal tract.
If you haven't already, please take a few minutes 
to look at our other videos in this series
on describing consonant sounds and 
navigating the international phonetic alphabet. 
In this video we will be talking about
how linguists describe vowel sounds.
Just a couple of notes. First again
like in the constant video 
we will only be talking about the phonetics of 
spoken language rather than sign languages
and we will be talking about the vowel sounds
as they are used in North American English.
There are two types of vowel sounds: 
Monophthongs and Diphthongs.
Monophthongs involve one vowel quality and
diphthongs involve too vowel qualities.
When linguists are describing vowel sounds, 
we have to rely on a different set of criteria 
for what we used in describing consonants because
remember, vowels do not involve the constriction 
of airflow in the vocal tract.
so our tongue doesn't approach an anatomical landmark like they do with consonants 
so the three criteria that linguists use
when describing vowel sounds are
height, backness and roudedness.
Let's talk about each of these in turn. 
Height refers to how high or or low the tongue is 
in the mouth when producing the vowel.
For example, consider the vowel sounds, [i] and [a].
If you say both of these vowels in succession,
you should feel your tongue going up and down
as you say [i], [a], [i], [a], [i], [a].
In terms of height, vowels are either
considered high, mid, or low.
[i] is an example of the high vowel.
[ɑ] is an example of the low vowel. 
Backness refers to how far front or back the tongue is 
when producing the vowel. 
As with vowel height, this can be tricky 
as it takes some practice,
but consider the vowels, [i] and [u]. 
If you say these vowels in succession, 
you may notice that your tongue is 
moving forward and backward 
as you say [i] [u] [i] [u] [i] [u].
In terms of backness, vowels are either 
considered front, central or back.
Remember that [i] is a high vowel 
but it's also a front vowel.
while [u] is a back vowel.
The third criteria that linguists use 
when describing vowels is roundedness.
Roundedness means whether or not 
the lips are rounded when producing the vowel.
This is something that's very easy as you can feel
and see when you are producing a rounded sound,
or when the person that you're talking to 
is producing a rounded sound.
so again take the two sounds that we just used.
[i] and [u]. 
[u] as you can clearly see and feel is a rounded vowel 
whereas [i] is not a rounded vowel.
[i] [u] [i] [u] [i] [u]
Just like with consonants there is a specific order 
that linguist use when describing vowel sounds. 
It is height, then backness, then roundedness.
For example, [u] is a high back rounded vowel.
[Ê] is a low front urounded vowel. 
Remember, so far we've only been talking about
monophthong vowels. 
If you want to categorize diphthongs in terms of these criteria
we must do so for by starting vowel quality 
as well as the ending vowel quality.
But we won't worry about that in this video.
Alright so what do we cover in this video?
We talked about the criteria that linguist use 
when describing vowel sounds,
and the order that those criteria must appear in, 
and that's pretty much it for this video. 
Be sure to check out our other videos and describing consonant sounds
and how to navigate the international phonetic alphabet.
I hope you enjoy this video. Thanks for watching. 
