User:JackLumber/-ae-/-e- and -oe-/-e-
Many words are written with ae or oe in British English, but a single e in American English. The sound in question is [i] or [ɛ] (or unstressed [ə]). Examples (with non-American letter in bold): paedophilia, anaemia, anaesthesia, caesium, diarrhoea, gynaecology, haemophilia, leukaemia, oesophagus, oestrogen, orthopaedic, paediatric. Words where British usage varies include encyclopaedia, foetus (though the British medical community deems this variant unacceptable for the purposes of journal articles and the like, since the Latin spelling is actually fetus), homoeopathy, mediaeval. In American usage, aesthetics and archaeology prevail over esthetics and archeology, while oenology is a minor variant of enology. In more modern legislative enactments, subpena is gaining currency over subpoena.
The Ancient Greek diphthongs <αι> and <οι> were transliterated into Latin as <ae> and <oe>. The ligatures æ and œ were introduced when the sounds became monophthongs, and later applied to words not of Greek origin, in both Latin (for example, cœli) and French (for example, œuvre). In English, which has imported words from all three languages, it is now usual to replace Æ/æ with Ae/ae and Œ/œ with Oe/oe. In many cases, the digraph has been reduced to a single e in all varieties of English: for example, oeconomics, praemium, and aenigma. In others, especially names, it is retained in all varieties: for example, phoenix, Caesar, Oedipus. There is no reduction of Latin -ae plurals (e.g. larvae); nor where the digraph <ae>/<oe> does not result from the Greek-style ligature: for example, maelstrom, toe. British aeroplane is an instance (compare other aero- words such as aerosol). The now chiefly North American airplane is not a respelling but a recoining, modelled on airship and aircraft. Airplane dates from 1907, at which time aero- was trisyllabic, often written aëro-.
International usage. In Canada, e is usually preferred over oe and often over ae as well; in Australia and elsewhere, the spellings with just e are increasingly used. Manoeuvre is the only spelling in Australia and the most common one in Canada, where maneuver and manoeuver are also sometimes found. Internationally, the American spelling is closer to the way most languages spell such words; for instance, almost all Romance languages (which tend to have more phonemic spelling) lack the ae and oe spellings (a notable exception is French), as do Swedish, Polish, and others, while Dutch uses them ("ae" is rare and "oe" is the normal representation of the sound u (while written "u" represents either the sound y or ʏ in IPA)). Danish and Norwegian retain the original ligatures. German, through umlauts, retains its equivalent of the ligature, for when written without the umlaut, words resemble the British usage (i.e. ä becomes ae and ö becomes oe). Similarly, Hungarian uses "é" as a replacement for "ae" (although it becomes "e" sometimes), and the special character "ő" (sometimes "ö") for "oe".