Prefixes are letters which are added to the beginning of the word to create another word with another meaning. For example, we add im to possible to create impossible.
We already know that identifying the stress in a word is difficult many times. However, when we talk about prefixes, this task is easier, because most prefixes don’t change the position of the word stress when they are pronounced, so most of them are unstressed.
We are going to focus here on three prefixes:
un- im- in-
These three prefixes are added to words to make their meaning negative. That is, we add un to happy to make unhappy, which means no happy.
It’s sometimes difficult to know whether one word take one prefix or another. Here you have some clues to make it easier:
Words beginning with m or n take im-.
For example: mobile à immobile or perfect à imperfect.
Words beginning with vowels (except i or u) or a consonant, take in-.
Thus, we have accurateà innacurate or decent à indecent.
Other words beginning with vowel or consonants may take un-.
So we have interesting à uninteresting or comfortable à uncomfortable.
in-, im-, un- are pronounced /ɪn/, /ɪm/, /ʌn/ and are not stressed, and we have to take into account that most of the times the words keep the stress in the original position.
Listen to the examples:
However, when we want to emphasize or make contrast between two opposite meaning, we stress de prefix. If we want to make sure that communication is taking place, we may want to emphasize the prefix so that the meaning is clear:
- I thought you said you were happy with him?
- No, I said I was unhappy.