Spelling: Spelling and word structure

Many common spelling errors occur with double consonants or vowel combinations, as in the following words:

• Double consonants: shipped, sadder, fittest
• Vowel pairs: advantageous, manageable

Sometimes these patterns are difficult to predict. But many letter pairs are predictable if you know how words are constructed out of their ‘building blocks’. These building blocks are called morphemes, and the study of these building blocks is called morphology. We add morphemes to root words (also sometimes called base forms) to create new forms. A morpheme added to the beginning of a word is called a prefix; a morpheme added to the end of a word is called a suffix.

In English, we often use suffixes to show

• whether a noun is singular or plural (typically, add −s),
• to show the tense of a verb (e.g. -ed added to the root for the past tense of a regular verb), or
• to mark comparative adjectives (fast → faster).