Understand an unknown word from its parts

In a B1 text many unknown words are in fact familiar: someone has simply added a prefix or a suffix to them. unemployment is employ ("give someone paid work") with un- ("not") added on the left and -ment (a suffix that makes a noun) added on the right: the situation when people have no paid work. If you know about twenty prefixes and suffixes, you can understand such a word without a dictionary, and build the form you need yourself.

How to take a word apart. First find the root — the familiar part. Then look at the prefix: it changes the meaning. Then at the suffix: it changes the part of speech, makes a noun from a verb, an adjective from a noun. The last step is to check your guess against the meaning of the sentence.

Prefixes change the meaning. The part of speech stays the same.

English has several negative prefixes, and the one word for "not" in your language may match any of them:

un- is the most common, especially before words in -able, -ful and -ed: unbelievable, unhelpful, unexpected. in- and its variants im-, il-, ir- more often go with words of Latin origin — the ones that have a twin in many European languages: incorrect — French incorrect, Spanish incorrecto; irregular — Spanish irregular, German irregulär. The last letter of the prefix changes to match the first letter of the word, so that it is easier to say. There is no reliable rule for which prefix to take, so you learn the negative form together with the word.

With a verb un- means the opposite action: lock — unlock (open with a key), pack — unpack (take things out of a bag or a box), do — undo (make it as it was before).

Other common prefixes:

Suffixes change the part of speech.

Some suffixes carry a clear meaning. -ful is "full of something", -less is "without": useful — it helps, useless — it doesn't help at all; careful — you pay attention so as not to make mistakes, careless — you don't. -able is "can be done": washable — you can wash it, readable — it is easy to read. -er is the person who does the action, and -ee is the person it is done to: employer — the person or company that gives the work, employee — the person who works for them.

In British English verbs are usually spelt with -ise: realise, organise, apologise. The variant in -ize is also found in British books, and in American English it is the only one.

A word family. A whole family grows from one root, and once you know the root, you understand all its members:

care → careful → carefully → careless → carelessly → carelessness

employ → employer → employee → employment → unemployed → unemployment

Compare. Pairs with -ful and -less are not always opposite in meaning:

The opposite of helpful is unhelpful, and helpless talks about something else. Taking a word apart gives you a guess; check the meaning against the sentence.

Spelling at the join. Four rules for how a word changes when you add a suffix:

• y after a consonant becomes i: happy → happiness, easy → easily, beauty → beautiful;
• a silent e disappears before a suffix that begins with a vowel, but stays before a consonant: use → usable, but useful; create → creation;
• in a short stressed syllable the last consonant doubles before a suffix that begins with a vowel: begin → beginner, win → winner, run → runner;
• -ful is spelt with one l: careful, beautiful. The adverb has two ls, because it is careful + -ly: carefully.

A prefix doesn't eat any letters: un + necessary = unnecessary (two ns), mis + spell = misspell (two ss), dis + satisfied = dissatisfied.

Stress. The suffixes -tion, -sion, -ity, -ic pull the stress onto the syllable right before them:

The suffixes -ment, -ness, -ful, -less, -er, -ly don't move the stress: employ → employment, happy → happiness. The exception is the photograph family: photographer, photography. The suffix -ee usually takes the stress itself: trainee, interviewee; but employee is more often said employee. Prefixes are usually unstressed: unhappy, impossible.

Don't say this. ✗ unhonest → ✓ dishonest. ✗ unregular → ✓ irregular. The negative prefix belongs to the word, and un- doesn't always fit.

Check yourself. What does unbreakable mean? Make nouns from kind and decide. Which syllable is stressed in possibility?