10 Grammar Mistakes Native English Speakers Make

English marks possession with ’s: the company’s logo, Sarah’s laptop. So when a writer wants “belonging to it”, it’s looks right. It isn’t. Possessive pronouns never take an apostrophe — his, hers, ours, yours, theirs, whose and its.

It’s only ever means it is or it has. That gives you a reliable test: expand the word. “The company changed it is logo” is nonsense, so you need its. “It has been a long week” works, so it’s is right. The same expansion sorts out who’s/whose (“Who is laptop is this?” fails → Whose), you’re/your and they’re/their. The form its’ does not exist.

Want more practice? Try the its vs. it’s exercises.

British writers call this the greengrocer’s apostrophe, after hand-written market signs like “Banana’s 2 for £1”. It is the mirror image of mistake 1: the writer knows that an s at the end of a word sometimes needs an apostrophe, and adds one to an ordinary plural.

A plural takes no apostrophe. An apostrophe appears only when the plural also owns something, and then it goes after the s: the Smiths’ house. Names already ending in s add -es for the plural: the Joneses, the Joneses’ car. For decades and abbreviations, current American and British style guides write 1990s and FAQs.

The one accepted exception is single lowercase letters, where the apostrophe prevents a misreading: mind your p’s and q’s, dot the i’s.

In ordinary speech the first vowel of both words is reduced to a quick, unclear sound, so affect and effect often sound the same. Writers then pick the spelling they see more often, which is usually effect.

For everyday writing, two facts cover almost every sentence: affect is a verb meaning “influence”, and effect is a noun meaning “result”. A quick check is substitution: if influence or alter fits, write affect; if result fits, write effect. Adjust the ending as you test — affected becomes altered, effects becomes results.

Two genuine uses break the pattern, which is why memory tricks such as “affect = verb, effect = noun” are only a starting point:

• Effect as a verb means “bring about”. The new director effected several changes means she made them happen. The new director affected several changes would mean she altered changes that already existed. The phrase you will meet most is to effect change.
• Affect as a noun is a psychology term for visible emotion: the patient showed flat affect. Outside clinical writing you are unlikely to need it.

Other sound-alike pairs worth a second look

In connected speech both words shrink to the same weak syllable, so “better then before” and “more then enough” turn up even in published writing. The two words do different jobs:

• Then is about time or sequence (We checked the data, then sent the report) or means “in that case” (If the server is down, then nothing will load).
• Than introduces a comparison: faster than, more than, rather than, other than, less than.

A practical check: if the word follows a comparative (more, less, better, rather, other, or any -er adjective), it is than.

Should’ve, could’ve and would’ve sound exactly like “should of”, “could of” and “would of”. The of spelling is an error in every variety of standard English. The full form is a modal verb plus have plus a past participle.

Note the second fix: “had of known” is not “had have known” — the extra word simply goes. If I had known is all you need.

Fixed phrases get rebuilt by ear in the same way. The writer hears a phrase, cannot see its logic, and substitutes words that seem to make sense. Linguists call these substitutions eggcorns, after a reported case of acorn written as “egg corn”.

What about “I could care less”?

This one is often listed with the eggcorns, but it is a different case. Nobody misheard a word: I could care less is a common informal American idiom with the same meaning as I couldn’t care less, and dictionaries such as Cambridge record it that way. Read literally it seems to say the opposite, which is why it irritates some readers; the usual explanations are sarcasm or a negative that dropped out in speech, and nobody knows for certain.

The practical advice is simple. In casual American conversation it is normal. In formal writing, and for British or international readers, use I couldn’t care less, which is accepted everywhere and is hard to misread.

Children say “Me and Sam went to the park” and are corrected: “Sam and I went.” The lesson many people keep is “and me sounds wrong, and I sounds educated”, so they use I after and even where an object is needed. Linguists call this hypercorrection. It is an old habit — between you and I even appears in Shakespeare’s The Merchant of Venice — but modern edited English treats it as an error.

The test is to remove the other person. Nobody writes “send the file to I”, so it must be to Anna and me. After a preposition (between, for, with, to, from) the pronoun takes its object form: me, him, her, us, them.

The same nervousness produces myself as a polite-sounding replacement: “Please contact Sarah or myself.” Myself is for when the subject acts on itself (I hurt myself) or for emphasis (I wrote it myself). As a plain object, write me: Please contact Sarah or me.

The textbook rule: who is a subject (Who called?), whom is an object (Whom did you call?). In practice, everyday English uses who for both, and Who did you invite? is standard, not a mistake. You do not need to “fix” it.

Whom is still expected in two places: directly after a preposition (To whom it may concern, the manager with whom I spoke) and in very formal documents. If you prefer to avoid it, you can usually move the preposition: the manager I spoke with.

The mistake careful readers do notice runs the other way: whom used where a subject is needed, because the writer is trying to sound formal.

The trap is the inserted clause we believed. Take it out and test the pronoun inside its own clause with he/him: “he was the strongest”, not “him was the strongest” — so who. The same test fixes “Whom shall I say is calling?” (he is calling → Who) and whoever/whomever: Give the badge to whoever needs it, because whoever is the subject of needs.

The rule taught in schools: fewer with plural count nouns (fewer emails), less with uncountable nouns (less time). This is a usage convention rather than a rule of English grammar — less with plurals has been used for centuries, and the strict version is usually traced to an 18th-century usage writer who offered it as his own preference. But it is the convention editors apply, so in formal writing follow it.

Do not over-apply it, though. Less is standard with amounts of time, money, distance, weight and age, because you are thinking of a quantity rather than counting units: less than ten minutes, less than $500, less than 5 km, children less than two years old. It is also idiomatic in one less thing to worry about. The supermarket sign “10 items or less” is everywhere and understood by everyone; in a report you would write fewer.

A related question that divides writers is whether none takes a singular or plural verb — see None Is or None Are?

Two verbs, one of which uses the other’s base form as its past tense. Lay means to put something down and always has an object. Lie means to be in a flat position and never has one. The collision comes in the past tense of lie, which is lay.

“Lay down” for “lie down” is extremely common in casual speech, especially in American English, and most listeners will not notice it. In writing that will be edited, keep them apart. Ask: is something being put down? If yes, lay/laid. If not, lie/lay/lain.

An opening phrase such as After reviewing your application or Walking to the station has no subject of its own. English readers attach it to the subject of the main clause that follows. If that subject is not the person doing the action, the sentence says something you did not mean.

The first version says you reviewed your own application. The fix is to make the doer the subject, or to give the opening phrase its own subject: After we reviewed your application, you were shortlisted. Form letters are full of these, because the writer is thinking about the reader and the sentence drifts to you.

A handful of opening words work as fixed connectors and do not need to match the subject: considering, given, assuming, judging by, generally speaking. “Considering the cost, the plan is reasonable” is fine.

Check yourself: ten questions

One question for each section above. Each has exactly one answer that edited English would accept.