The English language can be difficult to learn, both for native and non-native speakers. In many cases, bad grammar results from misunderstanding of proper usage and rules. Many errors are caused by the lack of subject-verb agreement, which occurs when the subject and verb of a sentence do not agree in person or number. Another common example of bad grammar is misusing pronouns, which have different forms depending on where they are used in a sentence. Incorrect usage of other words, such as adjectives and adverbs or relative pronouns, can also result in common grammar mistakes.
Bad grammar can result from errors in subject-verb agreement, which means that the subject and verb of a sentence must match each other in person and number. For example, a singular first-person subject such as "I" must have a singular, first-person verb. One common error associated with this grammar rule happens when the subject is a collective noun and is mistakenly paired with a singular verb. Another problem is created when two singular subjects are joined by the word "or" but are paired with a plural verb. Finally, when a singular and plural subject are joined with "or," the verb should agree with the subject closest to it.
Misuse of personal pronouns is another example of bad grammar. Pronouns can be difficult words to use correctly in English because, unlike nouns, different forms of pronouns are used as subjects and objects. The word "I" is always a subject, while the word "me" is always an object. Therefore, a sentence starting with "Bob and me went to the store," uses the word "me" incorrectly as a subject. The correct way to write this sentence is, "Bob and I went to the store."
Other types of bad grammar come from confusing adjectives and adverbs. An adjective is a word that modifies or adds additional description to a noun. Adverbs modify or describe a verb and can often end in "ly," such as in the words "quickly" and "easily." Using adjectives and adverbs improperly is generally considered to be bad grammar. For example, it is incorrect to say "He ran quick," because "quick" is an adjective. The correction is to use the adverb instead, "He ran quickly."
The words "who" and "whom" are relative pronouns that are frequently confused. "Who" is always the subject of a sentence, such as "Who are you?", while "whom" is always an object and is frequently used as the object of a prepositional phrase, as in "To whom am I speaking?" Sometimes "who" is used incorrectly as an object, as in the sentence, "The baby, who I babysit, is six months old." "Whom" is the correct word to use in this case.