Grammar reference library · Reference guide 6 of 6

Common Grammar Mistakes for Kids

A useful grammar-mistakes guide should do more than list “wrong” sentences. It should help a child identify the error family, explain why the form does not fit the meaning or structure, correct it, and then practise the underlying skill in a fresh sentence.

Understand the idea

What this grammar skill means

Grammar errors usually come from a smaller number of systems: noun reference and countability, subject–verb agreement, verb tense and form, question or negative structure, word order, sentence boundaries and word choice. Diagnosing the system turns correction into learning instead of one-time proofreading.

Why this skill matters

A child can correct a sentence after being told the answer and still repeat the same mistake in independent writing. The missing step is diagnosis. When children learn to classify an error and connect it to a rule they already know, they can monitor new sentences, explain corrections and transfer grammar knowledge into schoolwork rather than depending on an adult to mark every error.

Core rules and patterns

First identify the error family before changing the sentence. Ask whether the problem is about the noun, determiner, verb, sentence order or sentence boundary. For example, “many homework” points to countability and quantifier choice, while “She go to school” points to subject–verb agreement. This prevents children from making unrelated edits simply because a sentence looks unfamiliar.
Then explain the correction using meaning plus structure. “She goes to school every day” needs simple present because it describes a routine and goes because the third-person singular subject requires the matching present form. “Did she go?” needs the base form because did already carries the past marking. A reasoned correction is more transferable than replacing one word by memory.
Finally test the rule on a fresh sentence. After correcting “an advice” to “some advice” or “a piece of advice”, ask the child to use information, furniture or homework in a new sentence. After fixing a run-on, ask for a different pair of complete ideas joined accurately. The new example shows whether the child learned the grammar principle rather than copied the correction.

See the rule in context

Worked examples

Incorrect: She don’t likes maths. → Correct: She doesn’t like maths.

This is an auxiliary and verb-form problem. With third-person singular she in a simple-present negative, use does not/doesn’t. Once does carries the agreement, the main verb returns to the base form like. The repair is not merely deleting s; it is choosing the complete negative pattern.

Incorrect: I have many homeworks. → Correct: I have a lot of homework.

Homework is normally uncountable in standard English, so a plural homeworks and the countable quantifier many do not fit that noun meaning. The correction keeps homework uncountable and uses a quantity expression that can combine naturally with it.

Incorrect: Maya finished her work, she went outside. → Correct: Maya finished her work, and she went outside.

The original joins two independent clauses with only a comma, creating a comma splice. Adding a coordinating conjunction produces a correct compound sentence. A full stop or semicolon could also work in suitable writing; the key is to mark the boundary between two complete ideas.

More examples

He plays football every Saturday. — not “He play football every Saturday.”
Did they see the film? — not “Did they saw the film?”
I need some information. — not “I need an information.”

Common mistakes to watch

Correcting only the visible word without identifying the grammar system, which makes it difficult to apply the same rule in a different sentence.
Assuming every unusual sentence is wrong; some forms are grammatical but less common, stylistically marked or dependent on context, so the intended meaning must be checked.
Giving children a finished corrected sentence too quickly instead of asking them to locate the error, name the rule in child-friendly language and test the rule on a new example.

Watch for these

Tricky cases and useful distinctions

Not every difference is a grammar mistake. British and American English may prefer different spellings or some different forms, and spoken English can contain patterns that formal school writing avoids. The teaching goal is to use the standard expected for the child’s task while distinguishing genuine grammar errors from harmless variation.
One sentence can contain more than one error, but correcting all of them at once can hide the teaching point. For practice, isolate the main error family first. During authentic writing revision, work in passes: sentence boundaries, verbs, noun/determiner choices, then word choice and spelling. This reduces cognitive load and makes patterns easier to notice.

Try it

Short practice prompts

1.Classify twelve incorrect sentences by error family before correcting any of them: agreement, article/determiner, countability, verb form, question order, word order or sentence boundary.
2.Choose four corrected sentences and write a one-sentence explanation of the rule, then create a fresh example that uses the same rule accurately.
3.Edit a short paragraph in two passes: first fix sentence boundaries and verbs; then check noun/determiner choices and word order. Record which error family appeared most often.

Questions parents often ask

Quick clarifications

What grammar mistakes should children fix first?

Prioritise errors that affect sentence meaning and structure: missing or incorrect verbs, subject–verb agreement, sentence fragments or run-ons, question/negative structure and noun/determiner patterns. Then work on recurring word-order or usage issues. The best priority depends on the child’s actual writing sample rather than a universal list of mistakes.

Should a parent correct every grammar mistake in a child’s writing?

Usually not in one pass. Too many corrections can turn writing into copying. Select a small number of recurring error families, ask the child to find and explain the pattern, then test it in a fresh sentence. Keep content and ideas separate from grammar editing when possible so the child can improve both without losing confidence or ownership of the writing.

Continue the grammar reference library

← Previous: Word Order in English

Subject–Verb Agreement Countable & Uncountable Nouns Forming Questions Naturally Sentence Fragments & Run-ons

References and further reading

Sources used to check this grammar explanation

Tiny Steps writes the teaching explanation and examples independently. These references are provided for grammar definitions, usage patterns and further reading.

Common mistakes in English
Cambridge Dictionary
Corpus-informed reference grouping frequent learner errors in countability, determiners, prepositions, spelling, word choice, order and patterns.
English grammar reference
British Council LearnEnglish
Learner-focused grammar reference with explanations and examples.
Sentence Clarity
Purdue Online Writing Lab
Writing reference for clarity, sentence structure and appropriate active/passive choices.

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