Many complex words are derived from simple nouns and verbs through the addition of variable endings (known as ‘derivational suffixes’):
The spelling of complex words often follows general spelling rules, but these can be inconsistently applied, especially in newly formed words.
-able/-eable
When the suffix -able is added to a verb that ends in -e, the e is usually dropped. Spellings that retain the e are also around, but the simpler forms without the e are recommended:
The -eable form is more common in newly formed words (e.g. saleable, tradeable). When the verb ends in -ce or -ge (e.g. enhanceable, changeable), the e is retained to show that the c or g is pronounced as a ‘soft’ consonant (i.e. the c is pronounced as an s, and the g is pronounced as a j).
See also -ible/-able.
-ed/-t
Some verbs can be ended with -ed or -t: burn, dream, kneel, lean, leap, learn, smell, spell, spill and spoil. The -ed is generally used for the past tense and -t for the past participle or adjective:
The fire burned through 100 hectares of bush. The toast was burnt to a crisp.
His heavy speech spoiled the tone of the event. She behaved like a spoilt child.
-f/-ve
The plural spelling of nouns ending in -f is currently changing. A few that in the past took -ve have reverted to -f – for example, dwarfs (not dwarves) and scarfs (not scarves). Those that vary as plural nouns maintain the -f when used as verb:
hoofs/hooves hoofed
roofs/rooves roofed
-ian/-ean
The -ian ending is used for most adjectives derived from proper nouns, especially those formed in modern English:
The same goes for adjectives derived from other nouns:
The -ean ending appears in words formed from classical names with e in the final syllable:
A very few words can be spelled either way:
caesarean/caesarian Argentinian/Argentinean
Note: Either spelling can be used if referring to Caesar, the Roman emperor, but caesarean is the preferred spelling throughout the world for a surgical birth.
-ible/-able
The suffixes -ible and -able are used with many adjectives in English. Words that have come from Latin or French are usually written with -ible, but those formed in modern English from current verbs are written with -able:
admissible combustible compatible intelligible perceptible plausible
advisable changeable comparable desirable forgettable understandable
When in doubt, check a dictionary for whether -ible or -able is preferred. Words that do not appear in the dictionary – because they are relatively new or ad hoc – can be spelled with -able:
See also -able/-eable.
-ic/-ical; -istic/-istical
Some adjectives formed with either -ic or -ical endings have exactly the same meaning in general use:
But in other cases the meaning is different, and you will need to check to make sure you are using the correct form:
an astronomic rise in prices [a large increase] astronomical calculations [calculations made in astronomy]
comic [relating to comedy] comical [amusing]
economic issues [relating to the economy] economical with the housekeeping [keeping costs down]
a historic building [important because of its history] historical data [in the past]
Check formal names (such as those of gardens, zoos, societies and precincts) that contain interchangeable forms:
The -ly adverbs derived from these adjectives are always based on those with the -ical ending, whatever the meaning:
The same alternatives occur with -istic and -istical:
-ic/-ics
The names of many academic disciplines end in -ics (e.g. mathematics, classics, economics, physics, statistics, ethics). A few terms end in -ic (e.g. logic, rhetoric). In either case, such terms are treated as a singular collective noun:
Mathematics is hard work.
Logic is a mystery to me.
Politics is never balanced.
But when a term ending in -ics is made specific, preceded by a determiner (e.g. the, their) or adjective, it takes on a plural meaning:
The economics of climate change are complex.
Our current politics are very shallow.
-ify/-efy
These suffixes mean and sound the same, but the -ify ending is much more common; -efy occurs in only 4 words:
amplify beautify fortify gratify magnify notify purify quantify
liquefy putrefy rarefy stupefy
[The Macquarie dictionary gives liquify as an alternative to liquefy.]
-ise/-ize; -yse/-yze
Use -ise or -yse verb suffixes rather than -ize or -yze:
This includes the use of -isation in abstract nouns formed from -ise verbs:
Exceptions to this spelling rule in Australia are for proper names of some international organisations and programs (e.g. World Health Organization) or when quoting original material.
-ist/-alist
Many nouns describing occupations can be formed by adding -ist to either a noun or the related adjective (e.g. agricultural), with no difference in meaning:
In Australian English, the longer forms have traditionally been used. This may be changing, because the Macquarie dictionary gives preference to horticulturist.
-ment for verbs ending with -dge
Verbs ending in -dge can be spelled with or without the e:
abridgment/abridgement acknowledgment/acknowledgement judgment/judgement lodgment/lodgement
However, all English-speaking countries use judgment, without the e, in legal contexts.
Be consistent in retaining or dropping the e if more than 1 of these words is in your document.
-ogue/-og
Australians mostly use the -ogue ending rather than the -og ending:
Exception are analogue/analog and dialogue/dialog, which are used with different meanings in different contexts: analog in electronics, and analogue in literary and philosophical writing; dialogue for a conversation, and dialog in relation to computer software.
-os/-oes for plural nouns
For words ending in -o, some plurals are spelled with -oes, and some with -os. A few words are consistently spelled one way or the other:
echoes heroes potatoes tomatoes
avocados impresarios mementos pianos stilettos sopranos tamarillos
Check your dictionary for spelling, and make your text consistent.
-our/-or
Use the -our ending rather than the -or ending:
The -or spelling is often used in complex words derived from, or closely associated with, these words. However, there are exceptions:
arborist glamorous honorary laborious
but
armoury colouration favourable
program/programme
Program is the preferred spelling in the Macquarie dictionary for all uses of the word in Australia.
Did you know? Historically, British usage has distinguished between program for computer programs, and programme for all other uses. In the past, programme has been used in Australia in accordance with this tradition, and is still seen in some older titles.
However, the Oxford English dictionary has now endorsed program because it is a much earlier spelling than programme, and analogous with histogram, telegram and many other terms.
-re/-er
In Australia, the -re ending is almost always used where the spelling option with -er exists:
But the -re/-er endings mark an important difference in Australian English between metre (unit of distance) and meter (measuring instrument). Compound terms that refer to types of measuring instrument are always spelled with -er:
-se/-ce
In Australian English, some words end with -se when they are verbs and -ce when they are nouns:
He was licensed [verb] to take passengers.
They did not have a licence [noun].
She practised [verb] her bandaging skills.
He opened a second physiotherapy practice [noun].
Some pairs like this have different pronunciations: as z with -se and s with -ce:
advise [verb] advice [noun]
devise [verb] device [noun]
Although the -ce spelling is used with certain nouns in Australian English, the -s spelling is still used in words derived from them:
-us/-ous
Nouns ending in -us often come from Latin and are common in science. The adjectives related to them are formed by adding the English -ous ending – which sounds the same but is spelled differently:
See Chemistry terminology for further information about the correct usage for phosphorus and phosphorous.