Presentation on theme: "Perturbation Theory, part 2 November 4, 2014 Before I forget Course project report #3 is due! I have course project report #4 guidelines to hand out."— Presentation transcript:
Perturbation Theory, part 2 November 4, 2014
Before I forget Course project report #3 is due! I have course project report #4 guidelines to hand out. I’m still working on the grading of the Korean stops lab exercise. Let’s check out the mystery spectrogram!
Summary palatal glottal labial pharyngeal
A Note About F3 What about F3 distinctions? They’re unusual. For acoustic reasons: Intensity of voicing harmonics drops off at the higher end of the frequency scale (spectral tilt) And also auditory reasons: Sensitivity to frequency distinctions drops off in the higher frequency regions Note: F2 and F3 often merge for [i]
Decreasing F3 If we wanted to decrease F3... Where we would make constrictions?
Decreasing F3 If we wanted to decrease F3... Where we would make constrictions? Constrict at: lips “velum” pharynx
English English is distinctive because it has a very low F3. It has labial, post-alveolar (retroflex), and pharyngeal constrictions.
Synergy The labial, retroflex and pharyngeal constrictions all work together to lower F3. Similarly, both labial and velar constrictions lower F1 and F2 in high, back (round) vowels Synergy Interestingly, labial-velar vowels are far more common in the languages of the world than either: labial vowels velar vowels
Life’s Persistent Questions Let’s step back and review what our standing wave patterns look like in an open tube… And where they come from, exactly.
Back to Perturbation Theory Basic idea #1: vocal tract resonances (formants) are the result of standing waves in the vocal tract These standing waves have areas where velocity alternates between high and low (anti-nodes), and areas where velocity does not change (nodes)
Perturbation Principles Basic Idea #2: constriction at a velocity anti-node decreases a resonant frequency anti-node
Perturbation Principles Basic Idea #3: constriction at a velocity node increases a resonant frequency node
Labial Constrictions in the labial region are at anti-nodes for both F1 and F2. Labial constrictions decrease both F1 and F2
Labial Constrictions in the palatal region are at an F2 node and near an F1 anti-node F1 decreases; F2 increases Palatal
Labial Constrictions in the velar region are at an F2 anti-node and near an F1 anti-node F1 decreases; F2 decreases PalatalVelar
Labial Constrictions in the pharyngeal region are at an F2 anti- node and near an F1 node F1 increases; F2 decreases PalatalVelarPharynx
Labial Constrictions in the laryngeal region are at an F2 node and an F1 node F1 increases; F2 increases PalatalVelarPharynxLarynx
Different Sources For a particular articulatory configuration, the vocal tract will resonate at a certain set of frequencies… no matter what the sound source is. Let’s check out what Peter Frampton can do with a talk box… and the “Sonovox” Now let’s see what happens when we change our sound source to a duck call…
Duck Call Vowels duck call is placed here Now let’s filter the duck call with differently shaped plastic tubes…. Care to make any predictions?
Another View [i]
Duck Call Spectrograms [i]
Duck Call Spectra [i]
How About These? duck call is placed on this side
[i] vs. [e] [i][e]
[u] vs. [o] [u][o]
Philosophical Fragments Consider the Cardinal Vowels, again. An age-old question: Why are the high, back vowels rounded… And everything else unrounded? Rounding back vowels takes advantage of an acoustic synergy… which lowers both F1 and F2. But is there anything wrong with rounding the other vowels?
Five Vowel Spaces Many languages have only three or five vowels, separated evenly in the vowel space in a triangle Here’s a popular vowel space option: iu eo a
Gujarati Vowel Space
A “Bad” Vowel Space Five vowels in a vowel system are rarely, if ever, distributed thusly: [i] [e] [æ] Why?
Adaptive Dispersion Theory Developed by Bjorn Lindblom and Johan Liljencrants (Swedish speakers) Adaptive Dispersion theory says: Vowels should be as acoustically distinct from each other as possible (This helps listeners identify them correctly) So…languages tend to maximize the distance between vowels in acoustic space Note: lack of ~ distinction in Canadian English.
Unrounded Vowel Stats Number of languages with the following unrounded vowels (out of 316, from the UPSID database): i: 271 : 46 : 4 : 54 e: 83 : 4 (e: 113) : 77( : 6) : 116 : 6 : 4 æ: 38 a: 14(a: 274) : 22
Rounded Vowel Stats Number of languages with the following rounded vowels (out of 316, from the UPSID database): y: 21 : 6u: 254 : 3 : 48 ø: 15o: 88 : 5(o : 133) œ: 7 : 100 : 0 : 5
Rounded/Unrounded Ratio of number of languages with rounded vowels divided by number of languages with unrounded vowels, for particular parts of the vowel space: (22.2)
The Good, the Bad and the… High, front region of the vowel space: Unrounded vowels are preferred (good) (271) Rounded vowels are dispreferred (bad) (21) High, back region: Unrounded vowels are bad (4) Rounded vowels are good (254) Low, back region: Unrounded vowels are better (22) Rounded vowels are worse (5) Low, front region: Rounded vowels are really bad. (0)
Bad Vowel #1: [y] [y] has both labial and palatal constrictions Why is this bad?
Bad Vowel #2: [ ] [ ] has only a velar constriction Why is this bad?