American and British English pronunciation differences

French stress

For many loanwords from French, AmE has final-syllable stress, while BrE stresses an earlier syllable or preserves the original French equal stress per syllable.

Verbs ending in -ate

Most 2-syllable verbs ending in -ate have first-syllable stress in AmE and second-syllable stress in BrE. This includes castrate, collate, cremate, curate, dictate, dilate, donate, fixate, frustrate, gestate, gradate, gyrate, hydrate, lactate, locate, mandate, migrate, mutate, narrate_b, notate, phonate, placate_b, prostrate, pulsate, rotate, serrate, spectate, stagnate, striate, translate, truncate, vacate_b*, vibrate. Examples where AmE and BrE match include conflate, create, equate, elate, inflate, negate, sedate; and probate with first-syllable stress. Derived nouns in -ator retain the distinction, but those in -ation do not. Also, migratory and vibratory sometimes retain the distinction.

Most longer -ate verbs are pronounced the same in AmE and BrE, but a few have first-syllable stress in BrE and second-syllable stress in AmE: demarcate_a, elongate_a, impregnate, incarnate, inculcate, inculpate, infiltrate, remonstrate_ab, sequestrate, tergiversate_a^{[nb 1]}. For some derived adjectives ending -atory stress-shifting to -a(tory)- occurs in BrE. Among these cases are celebratory_a (BrE: /ˌsɛlɪˈbreɪtəri/), circulatory_a, compensatory_a, participatory_a, regulatory_a. AmE stresses the same syllable as the corresponding -ate verb (except compensatory, where AmE stresses the second syllable). A further -atory difference is laboratory: AmE /ˈlæbərətɔːri/ and BrE /ləˈbɒrətəri/.

Miscellaneous stress

There are a number of cases where same-spelled noun, verb and/or adjective have uniform stress in one dialect but distinct stress in the other (e.g. alternate, prospect): see initial-stress-derived noun.

-ary, -ery, -ory, -mony, -ative, -bury, -berry

Where the syllable preceding the suffixes -ary, -ery, -ory, -mony or -ative is unstressed, AmE pronounces the penultimate syllable with a full vowel sound: /-ɛri/ for -ary and -ery, /-ɔːri/ for -ory, /-moʊni/ for -mony and /-eɪtɪv/ -ative. BrE reduces the vowel to a schwa or even elides it completely: [-əri] or [-ri] (hereafter transcribed as /-əri/ in diaphonemic transcription), /-məni/ and /-ətɪv/. So military is AmE /ˈmɪlətɛri/ and BrE /ˈmɪlɪtəri/, inventory is AmE /ˈɪnvəntɔːri/ and BrE /ˈɪnvəntəri/, testimony is AmE /ˈtɛstəmoʊni/ and BrE /ˈtɛstɪməni/ and innovative is AmE /ˈɪnoʊveɪtɪv/ or /ˈɪnəveɪtɪv/ and BrE /ˈɪnəvətɪv/. (The elision is avoided in carefully enunciated speech, especially with endings -rary, -rery, -rory.^{[citation needed]})

Where the syllable preceding -ary, -ery, -ory, -mony or -ative is stressed however, AmE also usually reduces the vowel: /-əri/, /-məni/. Exceptions include library, primary, rosemary. (Pronouncing library as /ˈlaɪbɛri/ rather than /ˈlaɪbrɛri/ is stigmatized in the United States, for example as associated with African-American Vernacular English,^[1] whereas in BrE, /ˈlaɪbri/ is common in rapid or casual speech.)

The suffix -berry is pronounced by similar rules, except that in BrE it may be full /-bɛri/ after an unstressed syllable, while in AmE it is usually full in all cases. Thus we have strawberry: BrE /ˈstrɔːbəri/, AmE /ˈstrɔːbɛri/, and whortleberry: BrE/AmE /ˈhwɔːrtəlbɛri/.

The placename component -bury (e.g. Canterbury) has a similar difference: AmE has a full vowel: /-bɛri/ where BrE has a reduced one: /-bəri/.

Stress differences between the dialects occur with some words ending in -atory (listed above) and a few others like capillary (included in #Miscellaneous stress above).

Formerly the BrE–AmE distinction for adjectives carried over to corresponding adverbs ending -arily, -erily or -orily. However, nowadays some BrE speakers adopt the AmE practice of shifting the stress to the penultimate syllable: militarily is thus sometimes /ˌmɪlɪˈtɛrɪli/ rather than /ˈmɪlɪtərəli/, and necessarily is in BrE either /ˈnɛsəsərɪli/ or /ˌnɛsəˈsɛrɪli/.

-ile

Words ending in unstressed -ile derived from Latin adjectives ending -ilis are mostly pronounced with a full vowel in BrE /aɪl/ but a reduced vowel or syllabic L in AmE /əl/ (e.g. fertile sounds like fur tile in BrE but sounds like furtle in AmE).

AmE will (unlike BrE, except when indicated with) have a reduced last vowel:

• generally in facile, (in)fertile, fissile, fragile, missile, sterile, tensile, versatile, virile, volatile
• often in agile, docile,^{[nb 2]} ductile, futile, hostile, juvenile, (im)mobile (adjective and phone), puerile, tactile
• rarely in domicile,^{[nb 3]} erectile, febrile,^{[nb 4]} infantile, nubile, pensile, percentile, projectile, reptile, senile,^{[nb 5]} servile, textile, utile
• never in crocodile, exile, gentile, reconcile; nor to compounds of monosyllables (e.g. turnstile from stile)

In some words the pronunciation /iːl/ also comes into play:

• BrE /aɪl/, AmE /iːl/: c(h)amomile, mercantile, mobile/stabile (decorations)
• BrE /aɪl/, AmE /ɪl/ or /əl/: motile, prehensile, pulsatile, tractile
• BrE /iːl/, AmE /ɪl/ or /əl/: imbecile
• BrE /ɪl/, AmE /iːl/: rutile (BrE, AmE also /aɪl/)

Related endings -ility, -ilize, -iliary are pronounced the same in AmE as BrE.

di-

The pronunciation of the vowel of the prefix di- in words such as dichotomy, digest (verb), dilate, dilemma, dilute, diluvial, dimension, direct, dissect, disyllable, divagate, diverge, diverse, divert, divest, and divulge as well as their derivational forms vary between /aɪ/ and /ɪ/ or /ə/ in both British and American English.^[2]: 237

-ine

The suffix -ine when unstressed is pronounced sometimes /aɪn/ (e.g. feline), sometimes /iːn/ (e.g. morphine) and sometimes /ɪn/ (e.g. medicine). Some words have variable pronunciation within BrE, or within AmE, or between BrE and AmE. Generally, AmE is more likely to favor /iːn/ or /ɪn/, and BrE to favor /aɪn/.

BrE /aɪn/, AmE (1) /iːn/: carbine, Florentine, internecine, philistine, pristine^{[nb 6]}, saline, serpentine.

BrE /aɪn/, AmE (1) /iːn/ (2) /ɪn/: adamantine.

BrE /aɪn/, AmE /ɪn/: uterine.

BrE /aɪn/, AmE (1) /ɪn/ (2) /aɪn/ (3) /iːn/: crystalline, labyrinthine.

BrE (1) /iːn/, AmE (1) /aɪn/ (2) /ɪn/: strychnine.

Effects of the weak vowel merger

The weak vowel merger causes affixes such as -ate (as in climate), be- (before a consonant), de- (as in decide), -ed (with a sounded vowel), -es (with a sounded vowel), -est, -less, -ness, pre- (as in prepare) and re- (before a consonant) to be pronounced with the schwa /ə/ (the a in about), rather than the unstressed /ɪ/ (found in the second syllable of locksmith). Conservative RP uses /ɪ/ in each case, so that before, waited, roses and faithless are pronounced /bɪˈfɔːr, ˈweɪtɪd, ˈroʊzɪz, ˈfeɪθlɪs/, rather than /bəˈfɔːr, ˈweɪtəd, ˈroʊzəz, ˈfeɪθləs/, which are more usual in General American. The pronunciations with /ə/ are gaining ground in RP and in the case of certain suffixes (such as -ate and -less) have become the predominant variants. The noun carelessness is pronounced /ˈkɛərləsnəs/ in Standard Southern British and /ˈkɛərlɪsnɪs/ in conservative RP; both pronunciations typically merge in GA (usually towards the latter). This variation is denoted with the symbol ⟨ᵻ⟩ in some of the dictionaries published by Oxford University Press and in the Routledge Dictionary of Pronunciation of Current English. In the latter, the British pronunciation of climate is transcribed ⟨ˈklʌɪmᵻt⟩, though carelessness is transcribed ⟨ˈkɛːləsnəs⟩.

Affixes such as dis-, in-, -ing and mis- contain /ɪ/ in conservative RP as well as General American and Standard Southern British, so that words such as disloyal or teaching are phonemically /dɪsˈlɔɪəl/ and /ˈtiːtʃɪŋ/ in all three varieties.