Vowel quantity and vowel quality. English vowels, unlike their Spanish counterparts, may be divided into long and short, independently of the context in which they occur. A systematic account of the English vowel system shows length to be an important contrastive factor, though not the only one: the long vowels involve more muscular tension than the short ones and may therefore be described as tense, the short ones being lax. The I.P.A. notation highlights the importance of quantitative differences by incorporating the colon (:) in the symbols used for the ling vowels; attention is drawn to qualitative differences between vowels whose places of articulation are similar by using symbols that are similar but not identical. Thus, the symbols /i:/ and /I/ bear information about quantitative and qualitative differences between the two vowels.
Popular terminology. The popular terminolgy of vowels as being 'long' or 'short' is an attempt to bridge the gap between spelling and pronunciation. While such a classification is not taxonomic, it is not without its uses. The classifications are as follows:
English RP vowel system.
| symbol | name | unshortened | shortened | |
| 1 | / i: / | bead | beat | |
| 2 | / I / | bid | bit | |
| 3 | / e / | bed | bet | |
| 4 | / æ / | ash | bad | bat |
| 5 | / L / | caret | bud | butt |
| 6 | / a: / | card | cart | |
| 7 | /  / |
rod | rot | |
| 8 | / :
/ |
cord | caught | |
| 9 | / u / | pud | put | |
| 10 | / u: / | boozed | boost | |
| 11 | / 3: / | heard | hurt | |
| 12 | / 
/ |
schwa | pressures | precious |
English RP diphthong system.
| symbol | unshortened | shortened | ||
| 1 | / e I / | laid | late | |
| 2 | / a I/ | bride | bright | |
| 3 | /
I / |
joys | Joyce | |
| 4 | /u
/ |
flowed | float | |
| 5 | / a u / | bowed | bout | |
| 6 | / I / |
fears | fierce | |
| 7 | / e/ |
scares | scarce | |
| 8 | / u/ |
usual |
Fortis/lenis, voiceless/voiced. Most of the English consonants are arranged symmetrically into sets of fortis and lenis, terms that refer to the amount of muscular effort involved in their production. The terms voiceless and voiced are coextensive with fortis/lenis, but refer to the absence or presence of vocal cord vibration. The lenis series will be fully voiced when they occur between other voiced sounds (normally vowels); in initial and final position they will be partially voiced or completely voiceless.
Aspiration and devoicing. There is an appreciable degree of aspiration associated with the presence of the fortis consonants /p, t, k/ at the beginning of stressed syllables. (Aspiration is "a voiceless interval consisting of strongly expelled breath between the release of the plosive and the onset of the following vowel" Gimson 8.2.1) This aspiration is manifested in the devoicing of /l, w, r, j/ when the latter follow these plosives. There is no aspiration, however, when /s/ precedes /p, t, k/.
English RP consonant system.
| description | voiceless | voiced |
| Bilabial plosives | / p / | / b / |
| Alveolar plosives | / t / | / d / |
| Velar plosives | / k / | / g / |
| Palato-alveolar affricates | / t
/ |
/ d3 / |
| Labio-dental fricatives | / f / | / v / |
| Dental fricatives | / q / | / d / |
| Alveolar fricatives | / s / | / z / |
| Palato-alveolar fricatives | / / |
/ 3 / |
| Glottal fricative | / h / | / / |
| Bilabial nasal | / / | / m / |
| Alveolar nasal | / / | / n / |
| Velar nasal | / / | / h / |
| Lateral | / / | / l / |
| Post-alveolar frictionless continuant | / / | / r / |
| Unrounded palatal semi-vowel | / / | / j / |
| Labio-velar semivowel | / / | / w / |