Percentile ranks show where a score sits in relation to the normative sample. They indicate how a score compares to peers in the normative group—specifically, the percentage of individuals in the normative sample who scored at or below that score. For example, a percentile of 60 means the score is higher than about 60% of peers and lower than about 40%. This is different from a measure of distance from the mean (how many standard deviations above the mean), which would be a z-score; it’s also not a passing threshold or the raw number of correct items. In short, percentile ranks capture relative standing within the normative distribution.

Vowel reduction is when vowels in unstressed syllables lose their full, distinct quality and become a neutral, mid-central sound, most often realized as schwa /ʌ/. This happens to ease articulation in rapid or casual speech, so the syllable isn’t given the same acoustic prominence as a stressed one. In English, an everyday example is the first vowel in about, which is pronounced as /ʌ/ rather than a full vowel, and similarly in many unstressed syllables in words like banana, where the vowels tend to reduce to a schwa. The emphasis stays on the stressed parts of the word, while the others are shortened and centralized. So it’s not about vowels getting longer in stressed syllables, which would increase emphasis rather than reduce it. It’s also not about vowels turning into diphthongs in unstressed positions, which would change their quality in a different way, nor is it about nasalization from surrounding sounds in connected speech. The defining idea is this shift toward a neutral, mid-central vowel in unstressed contexts.

Voice Onset Time measures the interval from when a stop release happens to when the vocal folds start vibrating. A positive VOT means the voicing begins after the release—the order is release first, then vocal fold vibration. This pattern shows the stop is produced without voicing during the closure and a short lag before voicing starts, which is typical for voiceless stops. In contrast, if voicing started before or at release (negative or near-zero VOT), that would be characteristic of a voiced stop. For example, English voiceless stops like the initial p often have a noticeable lag before voicing begins, producing a positive VOT, whereas voiced stops like b typically begin voicing earlier, yielding a smaller or negative VOT.

Word-final position describes where a sound sits relative to the end of the word—the final segment you pronounce before the word boundary. In any word you can have initial, medial, and final positions; the final position is simply the last sound of the word. For example, in “cat” the final sound is /t/; in “happiness” the final sound is /s/; in “computer” the final sound is typically the rhotacized vowel /ʌ/ in many dialects. This is about the end of the whole word, not the end of a syllable, which can occur earlier within multisyllabic words.