Be careful in the use of the word retard in academic English. There are two uses in current English, one of which is to be avoided.
- The acceptable use is as a verb, 'to retard', with the general meaning of 'to make slower', 'to delay', 'to slow down, or make slower'. This is pronounced with the stress on the second syllable, 're-TAH(r)D' (IPA: /rɪt ˈɑːrd/.
- This meaning is reflected in the adjective retardant, ('re-TARD-'nt' /rɪt ˈɑːr dənt/), meaning 'delaying', 'slowing down'. This is perhaps most familiar in its substantive use in the compound fire-retardant - '[a chemical that] slows down the spread of fire'. (The use of such chemicals is now compulsory in the UK, by law, on upholstery, the wood of fire-doors, etc.)
- The current slang meaning of 'retard' as a noun (pronounced with the stress on the first syllable 'REE-tah(r)d', /ˈriː tɑːrd/, 'a person with learning difficulties', 'a mentally retarded [~backward] person': the sort of human being who is treated with contempt for being less mentally developed than other people around. The use of 'retard' to label such a person is insulting, as showing a lack if sensitivity to problems; to use 'retard' as a general insult for anyone is offensive.
AWE advises you NEVER to use retard as a noun in academic English. It is offensive slang.
- Historically, and in some technical fields even today, the noun retard can be used in a sense closely akin to the verb, meaning 'a delay', 'an adjustment of timing in a particular machine to improve its efficiency or working'.
- This pattern of shifting stress in words that look identical but belong to two separate word classes is quite common in English. Quirk (1985) (Appendix I.56 B) remarks: "When verbs of two syllables are converted into nouns, the stress is sometimes shifted from the second to the first syllable. The first syllable, typically a Latin prefix, often has a reduced vowel /ə/ in the verb but a full vowel in the noun:
- There follows a list of some 57 "words having end-stress as verbs but initial stress as nouns in Br[itish] E[nglish]." Note that "in Am[erican] E[nglish], many have initial stress as verbs also)". Quirk's list is the foundation of AWE's category:shift of stress. Additions have been made from, amongst others, Fowler, 1926-1996.