Jamaican English, which includes Jamaican Standard English, is a variety of English spoken in Jamaica. Like Canadian English (also part of the broad North American English classification), it resembles parts of both British English and American English dialects, but uniquely has many aspects of Irish intonation. Typically, it uses the same spellings as found in British English.
Jamaican Standard English is a variety of International Standard English (see English English). Since the mid-20th century, Jamaica has increasingly developed stronger social and economic ties with the United States and the increasing popularity of U.S. cultural offerings, including film, music, and televised dramas and comedies, exposure to American English has been increasing steadily.
Although Jamaica is closer to the United States, Jamaica was colonized by the British until 1962. Therefore, Jamaicans follow the British grammar, and British English is taught in school.
Recent American influence is apparent in the lexicon (babies sleep in "cribs" and wear "diapers" or "pampers"; some people live in "apartments" or "townhouses", for example). Generally, older vocabulary tends to be British (babies wear "nappies", not "diapers"; cars have "bonnets" and "windscreens"; children study "maths", use "rubbers" to erase their mistakes and wish they were on "holiday"), while newer phenomena are typically "imported" together with their American names.
The American term "trunk" is almost universally used instead of the British term "boot" on cars, while the engine covering is always referred to by the British term "bonnet" (as elsewhere throughout the English-official Caribbean). This is probably because the American term, "hood", is used in Jamaica as a vulgar slang for penis (but not elsewhere in the Caribbean).
Jamaican Standard English uses many words also used in Jamaican Patois, such as "duppy" for "ghost"; "vendah" for "informal vendor/hawker"; and some terms for Jamaican foods, like "ackee", "callaloo", "guinep", and "bammy".
Jamaican Standard English pronunciation, while it differs greatly from Jamaican Patois pronunciation, is nevertheless recognizably Caribbean. Features include the characteristic pronunciation of the /a?/ diphthong in words like MOUTH, which is often more closed and rounded  than in Received Pronunciation or General American; the pronunciation of the STRUT vowel /?/ to [?~o] (again, more closed and rounded than the British Received Pronunciation or General American varieties); and the very unique feature of "variable semi-rhoticity".
Jamaican English's rhoticity (the pronunciation of "r" everywhere except before vowels) is variable and can depend upon the phonemic context. Typically, Jamaican English accents fully preserve the "-r" in words of the NEAR and FORCE sets, drop the "-r" in words like LETTER (at the ends of unstressed syllables), show middling degrees of rhoticity in the SQUARE and CURE sets, and smaller degrees with all other sets of words. When "r" is followed by a consonant, non-rhoticity is nearly four times more likely than when "r" is at the end of a word. However, across the board, more rhoticity is positively correlated with higher levels of education.
Merger of the diphthongs in "fair" and "fear" takes place both in Jamaican Standard English and Jamaican Patois, resulting in those two words (and many others, like "bear" and "beer") often becoming homophones: the sound being [e:?], though often [i] (something like "ee-air"; thus "bear/beer" as "bee-air").
The short "a" sound (TRAP, man, hat, etc.) is very open [a], similar to its Irish versions, while BATH, PALM, and START all use this same sound too, but lengthened, and perhaps slightly backed; this distinction can maintain a London-like TRAP–BATH split. Both LOT/CLOTH and THOUGHT use a rounded [?], though a cot-caught merger is theoretically avoided by the latter set of words being more lengthened; however, in reality, a full merger (of LOT/CLOTH/THOUGHT) is reportedly increasing in informal contexts. For Jamaican Patois speakers, the merged vowel is much lower. GOAT and FACE vowels in the standard educated dialect are long monophthongs: respectively [o:] and [e:]. The unstressed schwa phoneme (COMMA) appears to be normally produced in the area of [a~?].
Presumably less-educated Jamaican Patois speakers may speak English with several other notable features, including a TRAP–LOT merger (e.g. with rat and rot homophones) to [?] and a PRIZE–CHOICE merger (e.g. with line and loin homophones) to [?i].
Jamaican Standard English and Jamaican Patois exist together in a post-creole speech continuum. Jamaican (Creole/Patois) is used by most people for everyday, informal situations - it is the language most Jamaicans use at home and are most familiar with, as well as the language of most local popular music. Standard English, on the other hand, is the language of education, high culture, government, the media and official/formal communications. It is also the native language of a small minority of Jamaicans (typically upper-class and upper/traditional middle-class). Most Creole-dominant speakers have a fair command of English and Standard English, through schooling and exposure to official culture and mass media; their receptive skills (understanding of Standard English) are typically much better than their productive skills (their own intended Standard English statements often show signs of Jamaican Creole interference).
Most writing in Jamaica is done in English (including private notes and correspondence). Jamaican Patois has a standardized orthography, and has only recently been taught in some schools. As a result, the majority of Jamaicans can read and write Standard English only, and have trouble deciphering written Patois (in which the writer tries to reflect characteristic structures and pronunciations to differing degrees, without compromising readability). Written Patois appears mostly in literature, especially in folkloristic "dialect poems"; in humoristic newspaper columns; and most recently, on internet chat sites frequented by younger Jamaicans, who seem to have a more positive attitude toward their own language use than their parents.
While, for the sake of simplicity, it is customary[by whom?] to describe Jamaican speech in terms of Standard English versus Jamaican Creole, a clear-cut dichotomy does not adequately describe the actual language use of most Jamaicans. Between the two extremes--"broad Patois" on one end of the spectrum, and "perfect" Standard English on the other--there are various in-between varieties. This situation typically results when a Creole language is in constant contact with Standardised English (superstrate or lexifier language) and is called a creole speech continuum. The least prestigious (most Creole) variety is called the basilect; Standard English (or high prestige) variety, the acrolect; and in-between versions are known as mesolects.
Consider, for example, the following forms:
(As noted above, the "r" in "over" is not pronounced in any variety, but the one in "dere" or "there" is.)
Jamaicans choose from the varieties available to them according to the situation. A Creole-dominant speaker will choose a higher variety for formal occasions like official business or a wedding speech, and a lower one for relating to friends; a Standard English-dominant speaker is likely to employ a lower variety when shopping at the market than at their workplace. Code-switching can also be metacommunicative (as when a Standard-dominant speaker switches to a more heavily basilect-influenced variety in an attempt at humor or to express solidarity).