Vowel tense-lax stress alternations

One complexity of the English stress and vowel system is vowel laxing when suffixes are added, that is, when a long or tense vowel reduces to a lax or short vowel with the addition of certain suffixes. This is part of the Latin stress pattern that English has inherited, and can pose challenges for learners, especially for those at intermediate to advanced levels as they learn more academic English with Latinate word elements.

The affected syllable is often the second from the end (the penultimate syllable, denoted here as "-2"), with a tense (long) vowel. As other Latinate suffixes are added, the syllable is now the third syllable from the end ("-3"). Here the vowel shortens to a lax vowel, e.g.,

Vowel = -2	Vowel = -3
nátion /neiʃən/	nátional /næʃənəl/
móde /mɔʊd/	módule /mɔdyu:l/

The addition of certain additional suffixes, incidentally, can cause the original primary stress to reduce to a secondary stress, e.g.:

nàtionálity

mòdálity

1 Tense – lax or long – short alternations

Note the following tense-lax alternations in word formation. With the addition of new suffixes, the stress shifts, and the tense vowels can become lax when they are three syllables or more from the end of the word. This also happens sometimes with shorter words with the addition of -ic, -id.

1.1 Glided /ei/ - lax /æ/

cave chaste exclaim defame deprave grade grain grateful grave humane inflame nation nature

cavity chastity exclamatory defamatory depravity gradual granular gratitude gravity humanity inflammatory national, nationality natural

navy opaque page pale placate profane rabies sacred sane state table vain vapor

navigate opacity paginate pallid placid profanity rabid sacrament sanity static tabular vanity vapid

1.2 Glided /i:/ - lax /ɛ/

appeal athlete austere brief clean clear compete concede convene creed diabetes deceive discreet extreme heal

appellative athletic austerity* brevity cleanliness clarity* competitive concession convention credible diabetic deception discretion extremity health

Hellene hygiene intervene meter obscene perceive proceed recede receive repeat serene severe steal sincere supreme

Hellenic hygienic intervention metric obscenity perception procession recession reception repetitive serenity severity stealth sincerity* supremacy

*Some of these are “r-colored” vowels, /ɛr/, that is, the vowel sound seems somewhat different due to the influence of the /r/.

1.3 Diphthong /ai/ - lax /ɪ/

arthritis Bible collide confide contrite crime cycle decide define dendrite derive describe divide divine elide expedite juvenile ignite inscribe line mime

arthritic biblical collision confident contrition criminal cyclical decision definitive dendritic derivative description division divinity elision expedition juvenility ignition inscription linear mimic

mine oblige parasite prescribe prime pyrite revise rite satire Semite senile sign saliva title transcribe triune type tyrant vile wide wild

mineral obligatory parasitic prescription primitive pyritic revision ritual satirical Semitic senility signal salivate titular transcription trinity typical tyranny vilify width wilderness

Also, in British pronunciation of -ile as /ail/, we see alternations like hostile, hostility; futile, futility.

1.4 Glided /ou/ - lax /ɔ/

code compose cone cyclone episode evoke expose globe holy hypnosis joke know locate microbe microscope

codify composite conic cyclonic episodic evocative expository globular holiday hypnotic jocular knowledge locative microbic microscopic

mode neurosis omen ozone phone provoke psychosis solo symbiosis telephone telescope tone trope verbose vocal

modular neurotic ominous ozonic phonics provocative psychotic solitude symbiotic telephonic telescopic tonic tropical verbosity vocative

1.5 tense /u:/ - lax /ʊ/

adjudicate assume consume crucify deduce duke induce numeral

adjudge assumption consumption crux deduction duchy induction number

presume produce punitive reduce repugn resume seduce

presumption production punish reduction repugnant resumption seduction

2 Other alternations

There is also occasionally destressing of these vowels with the addition of a suffix, such as the negative suffix -in:

famous finite potent

infamous infinite impotent

A few other such patterns also occur:

pronounce profound abstain maintain detain

pronunciation profundity abstinence, abstention maintenance detention

pertain persevere retain saline

pertinent perseveration retention salinity

Possible variations or exceptions: Some speakers vary in whether they shorten these syllables in a few words; this can depend on dialect or personal style.

penalize, phonological, economic, equinox, equatorial, equilateral, equidistant, homophone, hologram, amenable, placable, granary, nascent, predicate, simultaneous, sonorous, ammonic, patronize, patronage, microbic, gnomic, Hellenic, hydrophobic, finitude, homicide, myopic

3 Notes

3.1 See also

Portal:Phonology

  English vowels

  Trisyllabic deletion

  Trisyllabic laxing

  Vowel /eɪ/ phoneme (long vowel)

  Vowel /ou/ phoneme (long vowel)

  Vowel /æ/ phoneme

  Vowel /ʊ/ phoneme (short vowel)

  Vowel /ʌ, ə, ɜ/ phonemes (short central vowels)

  Vowel /ɪ/ phoneme (short vowel)