The Most Common Grammar Mistakes

These guidelines have been developed to highlight the most common grammatical mistakes and to provide practical recommendations on how to avoid these errors in academic writing.

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When writing for academic purposes, it is essential to deliver ideas in a clear and comprehensive way using language free of mistakes. However, the English language presents a variety of challenging issues, even for those students who know the language well. Grammar, encompassing the system and structure of a language, contains many controversial points that cause frequent confusion in common usage.


There are several most common grammatical mistakes often found in academic papers. They include usage of possessive and contracted forms, tenses, split infinitive, clauses, conjunctions, and linking words as well as subject-verb agreement and confusion of similar words. For each category, it is possible to provide more detailed recommendations on how to avoid the above-mentioned issues.

  • Possessive Pronouns and Contractions

Many students seem to be unaware as to the different usages of the apostrophe in English. An apostrophe followed by an “s” after singular nouns or without an “s” after a noun in the plural form is used to show that something belongs to somebody (Wallwork 64). Similarly, the apostrophe can also be used to indicate a contracted form of auxiliaries such as “is” or “has.” For example, “it’s” and “he’s” are the contracted forms of “it is” and “he is” or “it has” and “he has.” However, in academic writing, it is recommended to avoid using any contracted forms. Thus, students should only use an apostrophe to indicate possession and be careful to follow the rules applied to singular and plural nouns.

  • Tenses

When conveying thoughts within a text, it is crucial to preserve the same tense throughout a sentence if the described actions refer to the same period. The tense, as “the relationship between the form of the verb and the time of the action or state it describes”, should be appropriately applied within the text (Ho and Duong 55). Such consistency in tense usage will contribute to the flow of thought and will ultimately provide readers with a better understanding of the ideas discussed.

  • Split Infinitive

In spoken English, it is common to hear phrases similar to “we need to clearly identify it” where an adverb follows the particle “to” and precedes the verb. However, such usage is considered incorrect due to the split of the infinitive phrase that consists of two words: “to” and a verb. That is why, when writing a text, it is recommended to avoid ordering words in a manner that splits the infinitive. Thus, the correct way to write this phrase would be “we need to identify it clearly.”

  • Clauses, Conjunctions, and Linking Words

Compound sentences that consist of several clauses cannot be avoided in academic writing. Proper usage of commas, conjunctions, and linking words helps to avoid confusing statements and any misunderstanding by the readers. If the subordinate clause is placed at the beginning of a sentence, it needs to be separated with a comma. For example: “Although the protestors came out in the streets, the government did not change the policy.” When differentiating between dependent and independent clauses, it is essential to use conjunctions and commas correctly. Do not put a comma before “and” or “but” when they are placed between independent clauses in a sentence. Another commonly made mistake refers to “which” and “that” with restrictive and nonrestrictive clauses.

It is correct to use “which” for non-restrictive clauses that have to be separated with a comma. However, restrictive clauses should not be divided with commas because they contribute essential information to the sentence and have to be connected with “that.” When proofreading a written article, it is useful to check for proper punctuation in clause usage.

  • Subject-Verb Agreement

Another common grammar mistake is made when using verb forms for a particular subject form, referring to the “inflection of the verb to correspond or agree with the subject of the sentence” (Ho and Duong 55). In this case, the issue that normally leads to mistakes concerns words such as “everybody” and “nobody” that have a singular grammatical form but are often thought of as plurals. These words need to agree with the verbs in a sentence according to grammatical rules.

  • Confusion of Similar Words

Often, writers substitute a word with one that has similar spelling or pronunciation. Such mistakes lead to misunderstandings and indicate general poor writing quality. Some of the most frequently confused words include advice – advise, affect – effect, ensure – insure, and practice – practise. It is essential to differentiate between words that might seem the same but due to their similarities are often confused and cause mistakes in writing.


Summarizing the guidelines for proper grammar usage in academic writing, it is essential to be aware of the most common mistakes that students frequently make. The areas of error that appear the most widespread in academic writing include spelling, usage of articles, apostrophe placements, as well as punctuation issues in different parts of a compound sentence, and the confusion of words that sound similar but have different meanings. The recommendations given in these guidelines are aimed at facilitating students to avoid these errors and, in so doing, be able to produce high quality writing for educational purposes.

Works Cited

Ho, Pham Vu Phi, and Pham Ngoc Thuy Duong. “Common Errors in Writing Journals of the English-Major Students at HCMC Open University.” Journal of Science Ho Chi Minh City Open University, vol. 2, no. 14, 2015, pp. 52-61.

Wallwork, Adrian. Top 50 Grammar Mistakes: How to Avoid Them. Springer, 2018.

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