Final answer:
In English, the suffixes ic, al, ous, and oid are used to form adjectives that describe a characteristic or resemblance and are vital for vocabulary development. They attach to the end of root words and alter their meanings.
Step-by-step explanation:
The suffixes ic, al, ous, and oid are commonly found attached to the ends of words in the English language. The suffix ic often denotes pertaining to, or characteristic of something (e.g., historic, poetic). The suffix al is similar, indicating related to or pertaining to (e.g., personal, musical). The suffix ous typically signifies possessing, full of, or characterized by a quality (e.g., adventurous, courageous). Lastly, the suffix oid refers to resemblance or form (e.g., asteroid, humanoid).
These suffixes can significantly change the meanings of the words to which they are appended, and they are essential components of many English adjectives and nouns. Understanding how to use these suffixes can greatly enhance one's vocabulary and grasp of the language.