What's the difference between AFFECT and EFFECT?
AFFECT and EFFECT are often confused even by native speakers of English.
The most important thing to remember is that AFFECT is always used as a verb and EFFECT is normally used as a noun, but can also be used as a verb. When they are used in this way, they are similar in meaning, signifying an influence, an impact or a change.
Compare the following:
The really hot weather AFFECTED everybody's ability to work.
I know my neighbours play loud music late at night, but that doesn't AFFECT me. I can sleep through anything.
The number of tourists travelling to Britain this year has not been AFFECTED by the strength of the pound.
The tablets which he took every four hours had no noticeable EFFECT on his headache.
My words of comfort had little EFFECT. She just went on crying and wouldn't stop.
Note: we talk about someone or something having an effect on something or someone. If we use EFFECT as a VERB, it means to carry out or to cause something to happen, but it is used only in very formal English.
Consider the following:
Repairs could not be EFFECTED because the machines were very old.