Alright, so we're going to continue where the lecture that was posted as part 1 in suprasegmentals. A brief overview, we finished the
concepts we covered in the part 1, the concept of coarticulation, the concept of
assimilation we started talking about suprasegmentals the three primary
features of suprasegmentals will include intonation,
stress and duration, and then today we're going to continue talking about, so since we covered intonation
in our first part we're gonna finish up with stress and duration. So, what is Stress?
So in order to understand stress, we need to know what syllable is. Syllable is basically a binding of a consonant and a vowel. So, 'buh' is a syllable, 'cuh' is a syllable, so when you combine a consonant with a vowel
we get a syllable. Why is it important to understand syllable before we understand stress? Because
usually syllable is a unit of stress. We place our emphasis on certain syllables in certain words, which becomes
the emphasized word and that's what is called the stress. What is stress? Stress is
varying of a fundamental frequency, intensity, and the duration of the syllable. So when we
change the intensity of the syllable, when we change the duration of the syllable, or we change the frequency of
a syllable that is being stressed, those indicate that we are stressing a particular syllable other than the things. So sometimes
stress can be seen in a word level in a sentence. So for example this is my book versus this is my book. So that also
becomes a stress. The stress can be seen
syllable level and word level depending on if you're talking about what is the emphasis in a
sentence
I am a speech language pathologist, right, so my emphasis was on speech, rather than
I right? That indicates what stress is. Stress indicates which information in
the utterance is important. So in order to convey information, in order to convey meaning it is very important to see what, where we place the stress so
we know what utterance is most important. We, you know, good, a lot of good examples come to mind because we
work with a lot of our accent clients
People that come to our clinic for accent modification or accent change does a foreign speakers usually we try to work
on their stress because it's very difficult to place the right emphasis or the right stress on
certain parts of the sentence. So for example, I'm trying to come up with a good example, we work with one of our clients, where the emphasis in, I'm a medical doctor. So the emphasis is on medical versus
I am a medical doctor. So you see the difference. So placing stress becomes very important in conveying what information is important to convey. For example, the different types of stress
I have written here, in terms of lexical, one one such example is contrast of stress. In order to
differentiate between a noun and the word, the stress changes between the first part of
word versus the second syllable. The first syllable stress versus
second syllable stress. So good example would be contract and contract. I can say I have a contract that is
ready. I have to sign a contract to start my new job. That won't make sense but you have
to say I have to sign a contract to be, to take a new job. I have to say I contracted a
disease no that's not right a contracted
so it's very important to see what the differences in stress because it changes the
meaning that is being conveyed. So types of stress are multisyllabic stress, contrastive stress, and
derivative stress that are some of the main things that you seen at the lexical level. So the lexical level is moreso the syllable level.
So some of the example let's talk about this is multisyllabic stress is when there is more than one or two
syllables in a word and then the emphasis changes depending on the number of syllables in a word like, frequency
courageous, residual. Derivative stress is when you have a root word and then you derive from the root word to say something else.
Derivative stress. So the stress o economy is different from economic. So the stress is on
econ on that syllable for economy where the stress is on the n, economic on the no
for economic word. Similarly for derivative stress, democracy versus democratic. You see how this switch
happens from democracy versus democratic the syllables stress becomes on the 'cra' right
and we talked about contrastive stress is switching from the noun to the verb
If it's a noun, the emphasis, your stress, is on the first syllable, while if it's a verb the stress is on the second syllable.
So for example, permit versus permit. contract versus contract so those are some of
the things that you see as part of contrastive stress. It is important because it helps
us convey the meaning and I think I mentioned in the first part of the
lecture is that was one of the main things when I came, and even now sometimes
I do miss between saying, stressing the first versus the second syllable in contrastive stress. So it's very important, and it's very
important because speech is such a dynamic process and speech is so important in
conveying our emotions, conveying our intent, so it becomes very important because the we follow those suprasegmentals because it
forms a huge part of who you are what you want to convey, how you want to convey your emotions, so stress plays
an important role in indicating which information
in an utterance becomes very important. alright if I asked you what are the different types of
lexical stress, the three different types are multisyllabic stress, derivative stress, and contrastive. If you have to give an example, you need to be able to
give an example of each of this stress, lexical stress. Now how do we identify, of course when we
perceive, we presume that yes the emphasis was placed on this syllable, how do I know in an
acoustic analysis where the emphasis was placed? If you think about the emphasis of stress, when I'm stressing on a particular syllable, what are some of the things that I change? If you remember our lecture where we talked
about subglottic pressure, we said the minimal subglottic pressure required to initiate phonation is 3-5 cm of water. Then I said
as we place emphasis to, in order to place emphasis on a particular syllable we increase the subglottic pressure by 2 cm of water, so
when we increase the subglottic pressure by 2 cm of water, the queue that you will see is
called the greater intensity than a weakly stressed syllable. So you will se a
great intensity because of the emphasis because of the increase in the subglottic
pressure by 2 cm of water for a stressed syllable that indicated on an acoustic characteristics as a greater
intensity, darker striations on a spectrogram. Also with in terms of when you take emphasis or stress a particular syllable, you take more time to articulate that particular stress syllable.
That's why you see greater duration as another cue, acoustical cue, so you will see a longer duration of
that stress syllable compared to a weakly stressed syllable. The third acoustic character
you see is a higher frequency. The rise in subglottic pressure that we talked with
greater intensity will also assist in increasing the frequency slightly, I'm
not talking about a huge change in frequency, but I'm talking about a slight change in frequency
than when you compared to a weakly stressed syllable.
So three acoustic characteristics that are often associated with a heavily stressed syllable are high frequency, greater duration, and greater intensity than a weakly stressed
syllable. Okay, so what did we talked about stress so far we talked about stress is carried
in the syllable, right. So a syllable is the combination of a consonant and a vowel. Stress is seen in changes in
frequency intensity and duration of the syllable. Stress signals what
information is important in an utterance. Why is it important? Because it helps us
convey meaning very well, and then the types of lexical stress include a multi-syllabic stress, meaning more than two syllables in one
word, derivative stress where you're changing from one word and you're deriving another word and then contrastive stress. Contrastive stress is
important to understand the difference between noan and a verb. And when I ask you what are the
three important characteristics of a heavily stressed syllable it's higher frequency, greater duration and greater
intensity. The greater intensity is brought about by increase in subglottic pressure
which also assist in rising the frequency.
The greater duration is brought about by taking the longer time that you
take in producing that stress syllable. Okay, so those are what makes the stress in our speech. So stress contributes a
lot to out suprasegmentals of speech. The final primary feature of suprasegmentals is duration. Duration is the length of time of a
speech sound. How long is a speech sound being produced? Now that length of a time of a speech sound is going to be varying in term of .
of the context in which it occurs. Okay, so it varies by the degree of stress as we already talked
about. It varies with articulation depending on where it occurs in context with that articulation. So
let's talk about it for a second. Now we already said that it takes us time, there is a lot of time involved in
moving our articuators to produce a heavily stressed syllable,
when we do that there is increase in duration of that particular stressed syllable. Now, in
terms of articulation let's think about it. We already said that stops are non continuant sounds and cannot
be prolonged, right. While fricatives are long sounds that can be prolonged. So /s/
vs. /p/. You see how you can go /p/, that /p/ is a very transient sound vs. /s/. /s/ vs. /p/
so it varies with articulation, stops are shorter in duration than fricatives. Another things that happens is the vowels are a longer, the vowels are
longer if it occurs prior to a voiced consonants. So think about these two words
for me, the vowel /a/ islonger in the word
hard vs. heart. They're the same vowel sounds, okay even though the spelling is different, hard, heart, tab, tap. You see how the vowel sound is shorter, let me say that
/i/ is not the sound in tab and tap it's the /a/, tab, tap. So the duration is very important because it depends on the
context, duration is influenced by the context. The context could be because of heavily stressed syllable or
the context could be because of articulation of a speech sound, the manner of articulation of a speech sound, or it could also be depending on whether it occurs, how the vowel, sorry, how the vowel is changed in duration before a
voice vs. voiceless consonant. So it becomes a very important cue to differentiate between a voiced and voiceless sound is depending on the length of the vowel. So it serves as a cue for us and
even if you see on a spectrogram that whats you're gonna see on a spectrogram for heart vs. hard. You're gonna see that
the /a/ is gonna be longer in duration before the /r/ hard sound vs. heart. Which is gonna be
shorter in duration. Same thing for tap vs. tab. Tap and tab, okay. That's what, the increase in duration of the vowel sound if what is going to differentiate because the only thing that is different
is the voice and voiceless consonant at the end here. So, if you think about this
tab vs. tap, the only difference is one there is an increase in vowel duration before the
voiced consonant and the voiced and voiceless is the change, everything else stays the same.
So duration influences how we percieve sounds. Alright, I am sorry about that phone call, so you gonna
hear a ring and I paused the recording, so ignore that phone and just continue to go with the lecture. So we were talking about duration. Duration is very important because it
helps us perceive a voiced vs. voiceless sound, the vowels are gonna be longer before a voiced consonant and then it is gonna help us in term of stress, longer the duration of a particular sound, the more stress it's gonna have. So that kind of sums up our suprasegmentals.
So let's go over our suprasegmentals. We've talked about the three primary features of suprasegmentals, which is intonation, stress, and
duration. In terms of intonation we talked about it's basically the two acoustic cues
are your change in in frequency, your gonna have change in frequency and some change in intensity. The patterns of
change could be a fall or rise or just a rising pattern at the end of the utterance. It will signal
the type of utterance which is what's important. Intonation signals the type of utterance, while stress emphases what in
what in the utterance is gonna be important, what part of the utterance is important. And then we talked about stress, the three acoustic cues are gonna be
your fundamental frequency, duration, and intensity
and all of its gonna be the frequency is gonna be higher, the duration is gonna be greater and the intensity is gonna be greater which signals that it is a
a heavy stressed syllable. In terms of duration we talked about how it's the length of the speech sound
and the speech sound, the
length, the duration is gonna be varied in terms of context, the context could be the area of stress
the context could with articulation whether it's
occurring before a voiced, how to identify a voiced vs. voiceless consonant because the vowels are gonna be longer in duration. The final thing that I actually would like to kind to emphasis here
doesn't have to do with any of the suprasegmentals we've talked, is how do we understand between
a voiced and a voiceless sound?What are the cues that tell us a voiced versus a voiceless sound? The first cues is going to be a voicing bar or a voice bar.
we had talked about in our consonants part. And we talked about this is that little bar at the very
bottom that you can see on the spectrogram which indicates there is vibration on the vocal folds.
So a voice bar or a voicing bar on the spectrogram will say it is a voiced sound. Similar thing that tells about a voiced or voiceless specifically for stops is going to be a VOT. Voiced Onset Time. The time between the release of the burst or
the onset of vibration of the vocal folds to the next sound, that duration is going to be the voiced onset time.
longer VOT on the voiced sounds. Now we talked about on duration another queue is that the vowels
are longer when it occurs prior to a voiced sound than a voiceless sound. Example: Hard, heart. tap, tab. Bursts, we talked about noise burst which is a queue of
stops. Noise bursts are longer in duration for voiceless than voiced. And voiceless is characterized by aspiration which is kind of a spike at the end
of the stop
consonant ok. this is important because probably gonna be on the exam question I'm going
to ask you what are some of the cues, the acoustic cues to differentiate between a voiced and a voiceless consonant? Some of the cues here or voicing or voice bar, which is seen in
voiced and
not seen in a voiceless sound. VOT, which is longer for voiceless and shorter for voiced. Vowels are longer before a voiced consonant versus a voiceless consonant. And bursts are longer in duration for voiceless consonants than voiced. In voiceless another added cue to voiced is aspiration, ok. So that sums up this whole
part that we talked about how speech is a dynamic process, we talked about coarticulation, know the definition of coarticulation.
Know the definition of assimilation. How suprasegmentals play a huge role in conveying our attitudes, in conveying our emotions, meaning of utterances and the three parameters that are intonation, stress, and duration. Need to know the acoustic cues for all of those. And I also want you to kind of sum and know what the cues are to differentiate a voiced versus a voiceless consonant.