5 common grammatical errors and how to avoid making them

Do you ever worry about the grammar in your writing, and feel unsure how to fix it? Maybe you don’t have the time or money to get it professionally edited, or this may be overkill for, say, a personal blog post. Luckily, you can take other steps to reduce the chances of grammatical mistakes in your prose. Here we look at five of the most common errors, to help you identify and fix them. Note: an asterisk (*) before a phrase means it’s considered incorrect.

Subject–verb disagreement

Agreement is a common source of error in writing, as any proofreader or subeditor can tell you. When the grammatical subject is straightforward, mistakes are rare – no one with basic competence in English is likely to write, *The festival are starting, or *My favourites is chocolate.

But grammatical subjects are often more complicated than this, and subject–verb disagreement can then sneak in. Take this line: *Implementation of organisational checks and balances have improved. Because of the salience of the plural nouns checks and balances, and their proximity to the verb, the writer didn’t notice that the grammatical subject is the singular noun implementation. So have should be has. This kind of mistake is very common.

There can also be uncertainty over whether a singular or plural use is correct. What about collective nouns like team, staff, and government, and words like neither, as in Neither of the plans is/are perfect? These can all be singular or plural – just make sure their use is locally consistent and appropriate. Our post on grammatical concord explains this in more detail.

Comma splices

A comma splice is when you use a comma to join two independent clauses, as in It’s a sunny day, we’re off to the beach. Critics insist that such clauses be separated by a stronger mark than a comma, such as a semicolon, dash, or full stop, or by a coordinating conjunction, such as and or so.

The comma splice has long been used for stylistic effect, not just in casual writing but in literature, so its other names comma fault and comma error are a bit unfair.

But if you’re writing official or business English, it’s best avoided. In other contexts it should be used with caution, and only if you know what you’re doing, because many readers will consider it a mistake. You won’t find many comma splices on Macmillan Dictionary Blog.

Dangling modifiers

Dangling modifiers, though frequent in most varieties of English, have never become fully respectable, and perhaps for good reason. They’re often inconspicuous except to editors and pedants, but sometimes they stick out like a sore thumb and invite misreading. ‘It’s the funny ones that cause trouble,’ says the Columbia Guide to Standard American English.

This example from a motorbike magazine illustrates the point: From Llandrindod you proceed along the lovely valley of the Ithon, growing more beautiful as you proceed. The modifier growing more beautiful refers to the valley, but it attaches too readily to the pronoun you, suggesting that the motorcyclist is growing more beautiful as the journey proceeds. This post by Gill Francis has further examples and discussion.

Apostrophe catastrophes

Apostrophe errors are extremely common, especially when the possessive case is involved. Take the phrase the people’s choice, which means ‘the choice of the people’. This is often incorrectly styled as *the peoples’ choice, which means ‘the choice of the peoples’. Writers somehow forget, when they’re placing the apostrophe, that people is already plural. A similar mistake occurs with other plurals formed without an ‘s’, like children – instead of children’s, we get *childrens’. So be careful where you put the mark.

The use of its and it’s is another frequent source of error, and it can diminish authority. It can happen easily, because we think of the apostrophe as marking possessive case: I read Mary’s book, the cat’s bowl needs filling, but *The company found it’s way. To avoid this mistake, remember that it’s is always short for it is or it has. Its has the same pattern as other possessive pronouns like hers and theirs, which take no apostrophe: It’s time for its walk.

Strictly speaking, apostrophes fall under orthography rather than grammar. In general usage, though, grammar often refers to spelling, punctuation, and style, so we’ve included the apostrophe here.

Faulty parallelism

Faulty parallelism is a common lapse in style that sometimes entails grammatical error too. Parallel structure helps readers make sense of the material. When structures that should be parallel are not – through ignorance, haste, inattention, or lack of care – the prose is harder for readers to follow. For example, I could write that parallelism is important because:

  • makes reading more efficient
  • it improves clarity
  • because it enhances logic
  • courtesy to readers.

This list is legible but awkward, because the points are not structured in a parallel way. Instead, I could write that parallelism is important because it:

  • makes reading more efficient
  • improves clarity
  • enhances logic
  • is a courtesy to readers.

Here, each point follows naturally from the grammatical subject it, opening with a verb in the third-person singular. This makes the list a lot easier to follow.

Faulty parallelism also arises with constructions like as much (as) or more than. Writers often omit the second as, creating phrases like as good or better than we expected. This won’t be misinterpreted, and it’s OK in casual contexts. But you wouldn’t say as good than, so if you want to be strictly grammatical, include the second as, and consider adding commas: as good as, or better than, we expected.

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  • There are no common mistakes in language usage. The very idea is an oxymoron.
    If it’s common, it’s not a mistake

  • Jimmy: I wouldn’t go that far. Putting an apostrophe in possessive its is very common, for example, but by current standards it is unequivocally a mistake.

    Norma: That sounds like a bogus rule, or a guideline that’s been overapplied. There are multiple situations where a comma can be used legitimately before and.

  • Jimmy, just because someone consistently makes the same grammar mistake, it doesn’t make it any less of an error.

    Norma, not using a comma before ‘and’ is a stylistic decision. Traditionally, a comma was always placed before ‘and’ in a list or between the conjunction of two phrases.

  • Well said, John. Jimmy, I’ve always been told that it’s counterproductive to keep making the same mistake in life. I guess then, if I continue, it will no longer be one? So, if you make a big mistake in your law firm, to avoid dismissal, do it regularly?

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