Language Arts with Lyn Stone (St Monica's Wodonga)


Definition: a letter or letters placed before a base to alter the base’s meaning

Structure: pre- = before + -fix- = to fasten

Prefixes are fairly easy to teach, in that they are a finite set in English, that is, we aren’t making any new ones. The common ones constitute a relatively small list, easily taught and understood, since they are already in the everyday language of an average primary school child.

There are times when adverbs/prepositions are mistaken for prefixes, such as up (upward), over (overboard) and under (underestimate), and a good way to tell the difference is that if what you think is a prefix can stand alone, then what you have is actually a base plus a base. Contrast up, over and under with a word-forming element like trans- (transport, transatlantic). Trans- still indicates something to do with direction or movement, but it doesn’t stand alone.

An exception here is the prefix be- (become, beyond), which happens to look like the verb be, but etymologically speaking, they have different origins. Can you figure them out?


Sometimes prefixes can change, according to their environment. An immediately recognisable prefix like ad- (“to, towards”, advance, admit) also appears in other words as a-, and can even take on the first letter of the base it’s attached to (aggressiveaffectionappear). Of course it does, and so do other prefixes too. They have to, since ease of communication is our goal, so if they remained as ad-, that stoppy consonant /d/ would make it harder to speak.

Remember, placing of phonemes may look as if they are geographically distant, but in the rapid torrent that is the speech stream, minute placing adjustments make all the difference.

If you cast your mind back to the three musketeers of phonemes: voice, manner and placing, you’ll notice that there are distinct front, middle and back areas of the mouth. Speech is very rapid, and the distance between the lips and the throat is quite considerable at that speed. So phonemes change and words are formed according to order.

Take the sound /p/, for instance. Think it through using your three musketeers. Where was that sound made? How was it made? The front of the mouth with the two lips closed, right? So if a front of mouth sound begins a base, like the base pose for instance, a prefix that usually ends with a middle-mouth sound, like the prefix in-, doesn’t have time to travel from the front to the middle and becomes im-.

Taking -pose- again as our base, try adding the common prefix con-. What happens?

Some people call these ‘chameleon prefixes’, since they change according to their environment. That’s a good way to describe them. They are also known as assimilated prefixes

Let’s look at more assimilated prefixes and try to figure out why they act like that (clue: it’s always phonology!).

Here’s a key list of some common ones:

Chameleon prefixes

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Lyn Stone

My favourite chameleon prefixes are ad-, sub- and ex-. Do you have any others?