Lab 5: Glides and Liquids
Thomas Kettig, based on work by Sonya Bird et al.
Goal of Lab 5:
Sonorants are:
- similar to vowels in that they have formants
- different from vowels in that they are generally lower amplitude (and behave as consonants phonologically)
In this lab, we are going to explore the acoustic correlates of two types of sonorants: glides [w j] and liquids [ɹ l].
RECORDING
Go to eClass and download the zip file “Lab5_Soundfiles”, containing the following files. Note, you can also generate these yourself; I have done it for you here to make sure that the sound files are clear enough for taking measurements.
| File name | Sounds to record |
|---|---|
| Lab5_Wi_Ju.wav | wi, ju |
| Lab5_Ri_Ri.wav | ɹi, li, iɹ, il |
INSTRUCTIONS
SECTION I. GLIDES
- Open the file “Lab5_Wi_Ju.wav”. Follow the instructions below and fill in Table 5.1 on the acoustic correlates of different glides.
A. Formants
- In Table 5.1, note down the frequency of F1, F2 and F3 for each glide, as measured around the midpoint of the glide. The midpoint of [w] should be at about 1.23s and the midpoint of [j] should be at about 3.25s.
B. Formant transitions
- In Table 5.1, either draw stylized lines to indicate the F1, F2 and F3 contours throughout each Glide-Vowel sequence, or briefly describe in prose the path of the contours that you observe.
SECTION II. LIQUIDS
- Open the file Lab5_Ri_iR.wav. Follow the instructions below and fill in Table 5.2 on the acoustic correlates of different liquids.
A. Formants
Use only the coda [ɹ] and [l] (the 3rd word [iɹ] and the 4th word [il] in Lab5_Ri_iR.wav) for these measurements: formants are easier to see in coda position because they are more “stretched out”.
- In Table 5.2, note down the frequency of F1, F2 and F3 for each liquid, as measured around the midpoint of the liquid. The midpoint of [ɹ] should be at about 6.25s and the midpoint of [l] should be at about 8.3s.
B. Formant transitions
Again, use only the coda [ɹ] and [l] ([iɹ] and [il]) for these measurements.
- In Table 5.2, draw lines to indicate the F1, F2 and F3 contours throughout each VL sequence, or describe them in prose.
C. Formant transition durations: Onsets vs. Codas
Certain sounds are pronounced differently in onset vs. coda position, including liquids. In this last part of the lab, you will compare one acoustic correlate of liquids across syllabic positions: duration.
- Onset: Use [ɹi] [li] for the measurement of onset liquids. Measure the duration from the beginning of the Liquid-Vowel transition (where the formants start to move) to the point at which the formants stabilize in the following vowel (see Figure 5.1). Note down your measurement in Table 5.2.
- Coda: Use [iɹ] [il] for the measurement of coda liquids. Measure the duration between the beginning of the V-L transition (where the formants start to move) to the point at which the formants stabilize in the following liquid (see Figure 5.2). Note down your measurement in Table 5.2.
LAB 5 REPORT
SECTION I. GLIDES
Table 5.1 Acoustic correlates of glides
| [w] | [j] | |
|---|---|---|
| Formants (Glides) | F1: | F1: |
| F2: | F2: | |
| F3: | F3: | |
| Formant transitions (Glide-Vowel) as a drawing or a brief description |
Q1: Look at the formant structure of the glides: which vowel does each glide resemble?
Q2: Are any differences between the two Glide-Vowel contours, i.e. between the transitions out of the two glides? Articulatorily, what do you think causes these differences, and how are these articulatory differences reflected in the acoustics?
SECTION II. LIQUIDS
Table 5.2 Acoustic correlates of liquids
| [ɹ] | [l] | |
|---|---|---|
| Formants (Liquids) | F1: | F1: |
| F2: | F2: | |
| F3: | F3: | |
| Formant transitions (Vowel-Liquid) as a drawing or a brief description | ||
| Formant transition duration | Onset: | Onset: |
| Coda: | Coda: |
Q3: Make note of the differences between each liquid – which formant is most different between the two?
Q4: Do you notice any differences between the contours, i.e. between the transitions into the two liquids? What do you think causes these differences?
Q5: Compare the transition durations in onset vs. coda position (ɹi vs. iɹ and li vs. il) : which are longer?
Q6: Think about articulatory differences between /l/ in onset vs. coda position. Given what you know about these differences (think of the allophones of /l/ in English), do you expect any acoustic differences? If so, do your observations match your expectations?
REFERENCES
Q7: Provide a reference and very brief summary of one academic paper that uses the methods covered in this lab.
Disclaimer: The original lab materials on which this lab is based was put together in 2015 (updated 2019) by Sonya Bird, Qian Wang, Sky Onosson, and Allison Benner for the LING 380 Acoustic Phonetics course at the University of Victoria. Their materials are released under a Creative Commons license (CC BY-NC-SA 4.0) which allows for non-commercial use as well as copying and distribution and the creation of derivative works for non-commercial purposes. Thomas Kettig (with assistance from Taylor Potter) has modified these materials as needed for the York University LING 4220 Acoustic Phonetics course.