Definitions: Friction: when the spectrogram gets fuzzy and there’s usually not much of a coherent pattern visible.

In this case – the SS is an example of friction. The aspiration in the HK is also friction.

Closure: when there’s (usually) an abrupt decrease in energy and amplitude – the spectrogram will usually get a lot lighter abruptly.

Release: when, after a closure, there’s a burst of energy. The spectrogram will frequently show a dark vertical band.

Closure|Release Vowel onset: when the spectrogram develops a discernible pattern.

Vowel onset

Vowels: Vowels-nasals or nasals-vowels: Vowel/nasal transitions are usually fairly easy to locate. There is usually an abrupt change in energy between the two. That’s where the boundary marker goes.

AHNN – Boundary marker placed at location of abrupt change in spectral energy. Vowels-plosives or plosives-vowels: For vowels-plosives, look for the end of the vowel, which is usually marked by an abrupt change in energy. That’s where the boundary goes. For plosives-vowels, the boundary should go at the onset of the vowel, which is usually where you can discern a pattern in the spectrum.

HTOR – Boundary marker placed at the onset of the vowel.

Vowels-liquids & glides and vice versa: The boundary between these two can be tough to spot. General rule of thumb: look for the area of greatest transition. However, sometimes there really isn’t much of a transition, in which case I will try listening to see if I can hear where it starts. Sometimes even that doesn’t work very well, and I basically pick the middle (e.g. 50% in).

AOLX – Some spectral transition is apparent, but I still listened to find this boundary. Vowels-fricatives and fricatives-vowels: Look for an abrupt change in the spectral pattern. Between vowels and fricatives, I put the boundary where the pattern of the vowel ends. For fricatives-vowels, I put the boundary where the pattern of the vowel becomes discernible.

DHAH – Boundary marker placed at the onset of the vowel. AHSS – Boundary marker placed at the offset of the vowel.

Vowels-affricates and affricates-vowels: Treat affricates like plosives. For vowel to affricate transitions, place the boundary at the vowel offset. For affricate to vowel transitions, place the boundary at the vowel onset.

JHAH – Boundary marker goes at the onset of the vowel. AHJH – Boundary marker goes at the offset of the vowel. vowels-vowels: This one can sometimes be tricky, especially when dipthongs are involved. Again, the rule of thumb is to pick the area of greatest transition, although this doesn’t always work with dipthongs. If you’re stuck, try listening – that usually works for vowel-vowel transitions.

UWAX – In this case the transition is visible, but I listened to make sure the boundary marker was placed correctly.

Nasals: nasals-plosives or plosives-nasals: This can be another tricky combination, especially in words like “bend” and “rambo”. For nasal-plosives, look for a change in energy or a change in the spectral pattern. If there really isn’t any discernible change in anything, either pick a location 50% through or possibly about 50 msec before the burst. For plosives-nasals, look for the onset of the nasal.

NNDD – Boundary locatrion is placed at the location of the change in energy – the drop-out of upper frequencies KKNN – The boundary marker is placed at the onset of the nasal. nasals-liquids & glides and vice versa: Place the boundary marker at the onset and the offset of the nasal for these transitions.

RXMM – Boundary marker is placed at the onset of the nasal. Note: AARX – Boundary is placed at area of greatest transition. nasals-fricatives and fricatives-nasals: Again, the boundary marker is placed at the onset and the offset of the nasal for these transitions. There’s usually an obvious spectral difference between the two.

MMZZ – Boundary marker is placed at the offset of the nasal. nasals-affricates and affricates-nasals: Same as above. The boundary marker is placed at the onset and offset of the nasal.

NNJH – Boundary marker is placed at offset of fricative. nasals-nasals: Place the boundary marker at the onset of spectral transition. It may be necessary to listen to hear where the boundary marker should be placed.

NNMM – Boundary marker placed at area of spectral transition.

Plosives: plosives-liquids & glides and vice versa: Place the boundary marker between the plosive to liquid transition at the onset of the liquid and place the boundary marker between the liquid to plosive transition at the onset of the closure for the plosive. There should be a noticeable change in the spectral pattern between the plosive and the liquid/glide.

BBLL – Boundary marker goes at onset of liquid. plosives-fricatives and fricatives-plosives: For the fricatives-plosive transition, place the boundary marker at the onset of the closure for the plosive. The plosive-fricative transition, however, can be more difficult. Place the boundary marker where there is a change in the spectral pattern.

DDZZ – Boundary marker is placed after the release of the plosive and at the onset of the fricative.

SSTT – Boundary marker is placed at the offset of the fricative plosives-affricates and affricates-plosives: For the plosive-affricate transition, place the boundary marker where the affricate starts. If the affricate is unvoiced, there will be a noticeable change in energy level. If it’s voiced, you’ll see a change in the spectral pattern between the plosive and the affricate. For affricates- plosives, place the boundary marker at the onset of the plosive, which should either be where there’s a noticeable change in energy or a change in the spectral pattern.

DDJH – The boundary marker is placed after the burst and at the onset of the affricate. plosives-plosives: Frequently the first plosive will be unreleased when followed by a second plosive. In those cases it may be necessary to pick a boundary location 50% in. However, if there are two voiced plosives and no release, there may be a change in the spectral pattern. If one is voiced and the other is not, there will be a noticeable change in energy. If the first plosive is released, the boundary should go after the release and the accompanying aspiration.

TTKK – Boundary marker is placed after the release of the plosive, or, if no release, in the middle. plosive-silence: The boundary goes after the release of the plosive and when the strong aspiration has died down.

BB00 – Boundary marker placed after the release of the plosive.

Liquids and Glides: L/G-fricatives and fricatives-L/G: For the transitions between L/G and fricatives, place the boundary marker at the onset and offset of the L/G. There should be a fairly obvious change in the spectral pattern. LXFF – The boundary marker is at the offset of the liquid.

Note: AALX – The boundary is tough to spot, so I used the 50% rule. L/G-affricates and affricates-L/G: Again, place the boundary marker at the onset and offset of the L/G.

RXJH – Boundary marker is placed at the offset of the RX and onset of closure for JH.

L/G-L/G: This boundary location can be tricky. Sometimes there’s an obvious change in the spectral pattern that is where the boundary marker should go. Sometimes, however, there’s just a long, slow transition. In these cases try listening and at last resort pick a location 50% in. Fricatives: fricatives-affricates and affricates-fricatives: For fricative-affricate transitions, place the boundary marker at the onset of the affricate. For affricate-fricative transitions, place the boundary marker at the onset of the fricative.

SSCH – boundary at the onset of the CH, which is where the spectral energy in the upper frequencies dies out. fricatives-fricatives: Between 2 fricatives, there is usually some change in the spectral pattern. The boundary marker goes at the location of change.

VVZZ – The boundary marker is placed where the spectral pattern changes. Affricates: affricates-affricates: This case rarely occurs. I can’t think of an example. If it does, look for the area of spectral transition.