KS3 grammar: spelling


Spelling – introduction

The average 12-year old knows about 12,000 different English words (Shakespeare uses about 37,000). This may look like a large number to learn to spell if each is to be memorised by rote, but the task becomes a lot more manageable when memory is supported by understanding. Pupils need to be able to call on their knowledge of patterns and conventions to support their spelling. They also need a range of learning strategies, knowledge and the skill to spell words they want to use but have not seen in print before.

To know how to spell a word we have to use two kinds of knowledge:

  • phonological knowledge – that is, what we know about regular correspondences between phonemes (sounds) and graphemes (letters).

Phonological information has some relevance to the spelling of every word, however irregular. Phonological spelling patterns are already well established for most children by KS3; the spelling mistakes they make tend to be phonologically plausible. Although errors of omission are also quite common at KS3 and conflict with phonology, e.g. writing stat (for stand), many of these errors are the result of careless slips.

  • morphological knowledge – that is, what we know about the spelling of the morphemes (the smallest meaningful units of language) that a word contains.

Morphological information is relevant to any word that contains more than one meaningful unit, e.g. in laughed, the -ed can be predicted from the morphology, though not from the phonology. Morphological spelling patterns develop later and are much less well established at KS3.

  • Some words (a minority!) are exceptions e.g. laugh, thorough. These idiosyncratic spelling patterns have to be learned one by one, and direct teaching, perhaps with the help of mnemonics, may be necessary. At KS3, pupils should learn to recognise when they are uncertain and to consult a dictionary where necessary. It may help them to know that literate adults use dictionaries too!

Forming words from morphemes

This section on word formation looks at morphological patterns in words.

In order to know how English words are spelt it is important to understand some of the principles that govern the construction of words.

Morphemes are units of meaning within words –

un + dis + cover + able

Technical terms for morphology

Some of the terms you will need in order to understand and explain morphological spelling patterns are:

  • root words
  • compound words
  • affixes (prefixes and suffixes)
  • etymology (word derivations)

These terms are explained below.

Root words

Many words cannot be broken down into parts, for example:

boy, yes, person

These consist of the root only.

Since these words contain only one morpheme, the only knowledge about spelling that is relevant is either phonological or idiosyncratic: the spelling must either be predicted from the phonemes, or the word’s spelling must be learned as an exception to the general phonological spelling patterns.

Compound words

Roots may also combine to form compound words like football.

Affixes (prefixes and suffixes)

Other words contain a combination of the root and one or more affixes. Affixes are attachments at the beginning or end of a root word to modify its meaning. An affix is a morpheme that cannot stand alone. For example,

pre + script + ive

contains the root script with a prefix pre- and a suffix -ive. Affixes are either prefixes or suffixes.


Many words contain a prefix. A prefix stands before the root word. For example,


contains the morpheme pre (meaning ‘before’), which is found in many other words such as:

pre-war, predetermine, predecessor.

Other common prefixes are un (or in or im or ir), de, anti, re, co, sub.

There are no conventions governing the spelling of words when a prefix is added. Prefixes seldom affect the spelling of the root word. However, knowing the prefix boundaries and understanding the meaning of prefixes helps both spelling and vocabulary. For example:

  • knowing that unnecessary needs a double n because it means ‘not necessary’, so it consists of un + necessary;
  • knowing that there is only one s in disappear because it means ‘reverse the act of appearing’, so it consists of dis + appear.

Click here for a list of prefixes in the most commonly mis-spelt words.


Suffixes stand after the root word. Adding a suffix changes the spelling and the meaning of a word. Pupils need to know how suffixes work and the spelling rules involved; this knowledge will also help to deepen their understanding of grammar, and in particular of how morphology relates to syntax and meaning.

Click here for a list of suffixes in commonly mis-spelt words.

There are two kinds of suffix:


Derivational suffixes

These suffixes give related words different meanings and/or show that they belong to different word classes.

In this example,

prince – princess

the suffix –ess relates princess to prince, with a change of meaning indicating gender.

In this example,

derive – derivation – derivational

the suffixes ation (noun) and al (adjective) show that the words derivation and derivational are related to the verb derive, but are members of different word classes.

These derivational relations are the basis for the word families that pupils started to explore in the Literacy Strategy at KS2.

The following are some of the most common derivational suffixes, all of which feature in the KS3 spelling lists. They are given here with their grammatical functions in order to stress their importance in grammar as well as in spelling; notice how most of them give a relatively unambiguous clue to the word class of the word containing them.

  • ism  forms nouns from other nouns (e.g. race/racism, organ/organism);
  • ist  forms nouns or adjectives from nouns (e.g. tour/tourist, Buddha/Buddhist);
  • ful  forms nouns or adjectives from nouns (e.g. spoon/spoonful, skill/skilful);
  • ation  forms nouns from verbs (e.g. emigrate/emigration, civilise/civilisation);
  • ity  forms nouns from adjectives (e.g. moral/morality, able/ability, rapid/rapidity);
  • ly  forms adverbs from adjectives, (e.g. actual/actually, sincere/sincerely);
  • ise  forms verbs from adjectives or nouns (e.g. normal/normalise, synchrony/synchronise).

This list is by no means complete, and many of those not shown here are important for spelling.

Derivational suffixes can combine with one another, which gives great flexibility in creating new words but also leads to further spelling complications. For example, –ity can be added to -able, but the result is -ability (e.g. suitability); and when adverbs are formed by adding -ly to an adjective ending in -ic, the result is usually -ically (e.g. frantically). Notice that the first of these complications can be guessed from the pronunciation, but the second cannot.

Inflectional suffixes

These relate different forms of the same word.

In this example,

book – books,

The suffix s relates the plural books to the singular form of the same word.

There are very few inflectional suffixes but they are extremely frequent and important so it is essential for pupils to have a good understanding of their spelling as well as of their grammatical function.

The following are the regular inflectional suffixes, all of which feature in the KS3 spelling lists. They are given here with their grammatical functions in order to stress their importance in grammar as well as in spelling; notice how most of them give a relatively unambiguous clue to the word class of the word containing them.

  • s  marks a noun as plural, but a present tense verb as (third person) singular: e.g. The books look interesting but The book looks interesting; s changes to es after a hissing sound (e.g. hiss – hisses)
  • ed  marks a verb as either a past tense or a past participle: e.g. She walked or She has walked.
  • ing  marks a verb as a present participle: e.g. She was walking.
  • er  marks an adjective or adverb as comparative: e.g. quicker, sooner.
  • est marks an adjective or adverb as superlative: e.g. quickest, soonest.

This list is complete as far as regular inflections are concerned. Irregular inflections either lack the suffix entirely (e.g. took) or have an exceptional suffix whose spelling must be learned (e.g. kept).

Spelling conventions for adding suffixes

The most important morpheme-based spelling conventions are those for adding suffixes. The list of conventions and their exceptions may look formidable, but it simply brings together the knowledge that a literate adult writer of English has already acquired, and that KS3 writers are in the process of acquiring.

Their task will probably be easier if the rules they need to practice are presented explicitly. (If you would like to see how these rules apply in detail, try the Interactive Suffix Checker.)

Here are the main rules associated with adding suffixes.


Consonant doubling

This rule applies only if the suffix begins with a vowel, such as ed, er, able or ing.

If the root ends in a single vowel + consonant, the consonant doubles

hop > hopping

fit > fitter

stop > (un)stoppable

Notice how this doubling helps to distinguish such words from those in which final e has been omitted (see below):

hope > hoping (compare hopping)

ride > riding (compare ridding)

Doubling builds on a general tendency for vowels to be pronounced short before two consonants:

latter (compare later )

hurry (compare fury)

Exceptions to consonant doubling

    • the consonant does not double after two vowels:

      head > headed

hail > hailed

    • nor does it generally double if the root’s final vowel is unstressed.

      rocket > rocketed

      offer > offered

visit > visiting

    • final l always doubles after a single unstressed vowel in UK English (though not in US English):

      travel > travelling

equal > equalled

    • a final s may (but need not) double after a single unstressed vowel:

      focus > focussing  (focusing is also correct)

bias > biassed  (biased is also correct)

    • a final c changes to ck if the suffix starts with -i or -e:

      picnic > picnicking

panic > panicked

  • neither a final y or a final w doubles even after a vowel:

    play > playing

    draw > drawing


This rule applies only if the suffix begins with a vowel, such as ed, er, able or ing.

A final unpronounced e after a consonant is omitted:

save > saving

love > lovable

shade > shady

This process is understandable if we remember that the silent e is used only as a ‘dummy’ vowel to show that the preceding vowel is long, building on the general tendency for single vowels to be pronounced long before a single consonant followed by another vowel:

later (compare latter)

fury (compare furry)

Once the suffix provides another vowel, the silent e is no longer needed.

Two consequences of this are:

  • the final e is not dropped after a vowel:

    see > seeing

    dye > dyeing

  • the final e is not dropped before a suffix whose first letter is a consonant:

    excite > excitement

    definite > definitely

Exceptions to E-dropping

    • e is dropped after u even if the suffix begins with a consonant:

      true > truly

argue > argument

  • If the final consonant of the root is c or g and the suffix starts with a or o, the e is retained in order to show that the root consonant is ‘soft’:

    replace > replaceable (but replacing)

    courage > courageous (but raging)

(Very exceptionally, e may occasionally be dropped before a suffix that starts with a consonant – for example in judgment, an alternative spelling of judgement.)

  • Some words allow two spellings, with or without e, if the suffix isable:

    like > likable  or likeable

    move > movable  or moveable

Y to I

This rule applies, if the y follows a consonant, before any suffix, whether the suffix begins with a vowel or a consonant.

Change y to i between a consonant and a suffix:

hurry > hurried

marry > marriage

fury > furious

merry > merriment

    • If the y follows a vowel, it does not change:

      play > played

enjoy > enjoyable

  • Note that a final -ie changes to -y before -ing

    lie > lying

    die > dying

Exceptions to Y to I

    • no change before i (in order to avoid the sequence ii):

      try > trying

baby > babyish

  • add e before the suffix -s

    hurry > hurries

    duty > duties

Changes before plural -s

A few nouns (all ending on -o) add e, though most do not:

potato > potatoes

tomato > tomatoes

hero > heroes

A few nouns change f to v, (with or without silent e) but most do not, and the difference can be heard in pronunciation:

calf > calves

life > lives

Compound words

Compound words are formed by joining two root words, e.g. armchair, cupboard, football.

Most compounds are straightforward to spell because they consist of two words simply joined together, e.g. postcard, handbag. When compound words are formed, the spelling of the root words usually remains unchanged.

In order to spell other compound words, however, it is useful to know how they are formed and their derivations,

e.g. cup + board

The spelling of some compound words preserves earlier pronunciations, which we have now simplified by merging groups of consonants into a single one and/or by shortening the vowels. Understanding the derivation of a compound structure can help pupils to understand and remember the spelling of words such as:




(For more on the conventions governing the use of hyphens in compound words click here.)


It is important for pupils to know that our words come from several different sources, and that this is reflected in their spelling. This is one of the reasons why English spelling is so ‘un-phonetic’. For example, the ph in the word phonetic shows that this word is derived from Greek (phone, meaning ‘sound’). Pupils who understand some of the clues to the origin of words will find that this helps their spelling.

The study of word origins is interesting and important, and pupils should be encouraged to use etymological dictionaries. Every word has its own history, and often these quirky details are fascinating – for example, most people are interested to learn that the word glamour is based on the word grammar!

More about etymology and the derivation of words

Words in which the grapheme ph corresponds to the phoneme /f/ are always from Greek: e.g. philosophy, grapheme, morpheme. The same is true of most words that end in ic (e.g. music, antic, phonetic), though some of these come from Latin (e.g. public). Pupils whose home language is Greek should be encouraged to use this knowledge to guess English spellings; those who know no Greek can at least learn to distinguish between Greek-based and other words.

However, as far as spelling is concerned, the following broad categories are helpful:

  • Native words: i.e. words that we inherit from the English brought to England by the Germanic migrants (Anglo-Saxon, heavily influenced by the language of the Vikings). About half our vocabulary is native, and this includes the most common everyday words.
  • Words from Latin, which for many centuries was the only language used in scholarship. This is why it has provided so much of our technical and learned vocabulary (e.g. the word vocabulary). Many Latin words themselves come from Greek.
  • Words from Greek, which are widespread in the areas of knowledge that were first developed by the ancient Greeks (e.g. geometry, philosophy).
  • Words from other languages – Arabic (algebra), Italian (spaghetti), Spanish (armada), German (kindergarten), Hindi (shampoo) and many others.

One particular area of difficulty (and interest) is the inflectional morphology of some nouns derived from Latin or Greek, whose plurals follow the pattern of the source language rather than of English. For example, cacti shows the regular Latin plural for a noun ending in -us – a very un-English pattern – and similarly for oasis/oases, formula/formulae and others.

Other nouns with plurals based on the source languages that pupils may meet in KS3 are:

-a > -ae: formulae, antennae, vertebrae, algae

-us > -i: stimuli, fungi, foci, nuclei

-um > -a: bacteria, strata

-ix or -ex > -ices: matrices, indices

-is > -es: analyses, bases, oases, crises

-on > -a: criteria, phenomena, automata

Many scientific words contain Latin and Greek roots.

Pupils meet such words in their reading at KS3, and should be made aware of their morphological peculiarities. However, these words do not feature at all in the KS3 spelling lists, so more serious study can probably be delayed until KS4.

Homographs and homophones

KS3 writers may still find difficulty in distinguishing between some homographs. Also, they often make spelling mistakes in using homophones, and these will usually need explicit revision.

  • homographsHomographs (from the Greek words homos, meaning ‘the same’ and graphein, meaning ‘write’) are words that are spelt the same, but have different meanings and, often, different pronunciation; for example:

    bow as in bow and arrow
    bow as in bow down

    minute as in a minute creature
    minute as in wait a minute

    In dealing with homographs, pupils need to understand the context if they are to select the correct meaning and pronunciation, since the spelling gives no clue.

  • homophonesHomophones (from the Greek words homos, meaning ‘the same’ and phone, meaning ‘sound’) are words which are pronounced the same, but which have different spellings and meanings; for example:

    feet / feat

    knight / night.

    In most cases the spelling of these words, along with their meanings, needs to be taught directly. Many homophone choices are best taught as grammatical issues, e.g. there/their/they’re. Analogy with other members of the same word family can also be helpful, e.g. our/your; here, where, there.

    If pupils use a spellchecker, they need to know that it will highlight only those words that are not correctly spelt English words; it will miss incorrect homophones, e.g. There putting they’re shoes their.


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