Four of the most confusable words in English are adopt vs adapt and aide vs aid.
Aide vs. Aid
These two words have essentially the same meaning, which is assistance, yet their applications differ. ‘Aide’ always refers to a person who assists. ‘Aid,’ on the other hand, refers to anything not human that assists or is assistance. It can be a noun or a verb. In the following example, ‘aid’ is a noun: “Financial aid is provided to students.” Here, it is a verb: “The nurse aids the doctors in patient care.” Yet, if we change the word to describe who the nurse is rather than what she does, we get the following: “The nurse is an aide to the doctor.”
Adopt vs. Adapt
To adopt means to take in or acquire. It indicates that one has something he did not have before. To adapt means to alter according to circumstances or environment. You can’t adapt what you don’t have, and can’t adopt what you already have.
A simple trick to differentiating between these two similar words is to think of a phrase in which one is commonly used. “Adopted child,” for example, is a very well-known usage of the words ‘adopt.’ When one adopts a child, he takes the child into his family. The word ‘adapt’ is often used in discussions of biological evolution. Species that quickly adapt to their environment survive. If one keeps these common uses in mind, it will help in selecting the proper word.