Glossary of speech features

Nasality
a phonetic feature related to whether the consonant sound comes out of the mouth or the nose. For example, the words “mat” and “bat” start with a nasal /m/ and a non-nasal /b/ respectively. Difficulty hearing the nasality feature makes these words sound alike.
Vowel height
a low-frequency phonetic feature related to tongue height for vowels. For example, the words “court, curt, kit” have low, mid, and high vowels respectively and if they sound alike then you are having difficulty hearing the vowel height cues.
Manner
a phonetic feature related to how consonants are produced, with the acoustic information spread across a wide range of frequencies. For example, the consonant /p/ is a stop, /L/ is a glide, /ch/ is an affricate, /n/ is a nasal and /f/ is a fricative.
Voicing
a low-frequency phonetic feature related to whether your vocal folds are vibrating when you produce consonants. For example, the words “tough” and “duff” have unvoiced and voiced consonants at the start. If they sound alike then you are having difficulty hearing voicing.
Contour
a mid-frequency phonetic feature related to tongue movement. For example, when you say the words “bout” and “bait” the highest point of the tongue moves backward or forward in the mouth. Difficulty hearing the formant transitions or contour of sounds makes these words harder to tell apart.
Vowel place
a mid-frequency phonetic feature related to tongue position for vowels. For example, the words “hoard, hard, heed” have back, central, and front vowels respectively. Difficulty hearing vowel place makes these words sound alike.
Vowel length
a phonetic feature related to the duration of vowels. For example, the words “hit” and “heat” have short and long vowels and if they sound alike then you are having difficulty hearing vowel length.
Affrication
a mid-to-high frequency phonetic feature used to classify noisy sounds such as /f/ or /s/ or /v/ that are produced by air rushing through a small constriction in the mouth. If “fin” and “tin” sound alike, for example, this would be an affrication error because the fricative /f/ is confused with the non-fricative /t/.
Sibilance
a high-frequency phonetic feature to characterise the /s, z, sh, zh, ch, dzh/ consonants. If you can’t hear these consonants clearly then you will have trouble telling whether words are singular or plural, particularly over the phone where high frequencies are diminished.
Consonant place
a high frequency phonetic feature related to where consonants are produced in the mouth. In English there are seven different places of articulation: glottal, velar, palatal, alveolar, linguadental, labiodental, bilabial. Examples are /h, g, sh, t, th, v, b/. Difficulty hearing consonant place makes the words “gut” and “but” sound alike. We use a simplified version with only three categories – back, central and front.