Common Grammar Mistakes

Common Grammar Mistakes is a clear guide to the English grammar mistakes that learners and native speakers make most often: 59 topics in 10 sections, from their/there/they're and who or whom to comma splices and commonly misspelled words.
Each page explains the rule in plain language, shows correct and incorrect example sentences side by side, and ends with practice questions. It works offline.

Many common English mistakes come from words that sound alike, from rules nobody explained clearly, or from habits that spell checkers do not catch. This app shows the mistake, the correct sentence and a simple way to remember the difference.

What you will learn
• Confusing words: their/there/they're, your/you're, to/too/two, affect/effect, lose/loose, accept/except, principal/principle, compliment/complement, advice/advise, lead/led, breath/breathe, past/passed, weather/whether, peek/peak/pique, into/in to, a lot/alot/allot, everyday/every day, assure/ensure/insure, imply/infer, borrow/lend and i.e./e.g.
• Pronouns: I or me, myself and other -self words, who or whom, that or which, its or it's, whose or who's
• Agreement: subject–verb agreement, tricky subjects (each, none, collective nouns, a number of), pronoun–antecedent agreement and singular they
• Verbs: lie or lay, tense consistency, could of/should of/would of, irregular past forms, and if I were or if I was
• Modifiers: dangling modifiers, misplaced modifiers, good or well, bad or badly
• Comparisons: fewer or less, than or then, farther or further, between or among, and comparative and superlative mistakes
• Sentence structure: run-on sentences, comma splices, sentence fragments and parallel structure
• Punctuation mistakes: apostrophes, commas, semicolons and colons
• Spelling: 67 commonly misspelled words with a tip for each, useful spelling rules (i before e, doubling, -able or -ible) and American and British English
• Review: the 12 most common mistakes on one page, a mixed quiz of 24 questions and a quick-reference A–Z index

Features
• 59 English grammar topics in 10 sections
• Correct examples marked with a green check, incorrect ones with a red cross
• Memory tips that make confusing words easy to tell apart
• 165 practice questions with tap-to-reveal answers, including the 24-question mixed quiz
• Searchable list of commonly misspelled words and a searchable A–Z index
• Search all pages from the home screen
• Dark mode
• Works offline, no account needed
• Explanations available in 8 languages: English, Español, Português, Français, Deutsch, العربية, हिन्दी and Bahasa Indonesia (example sentences stay in English)

Who it is for
• English learners at intermediate level and above who want to stop making the same grammar mistakes
• Students writing essays and preparing for English tests
• Anyone who wants to write clear, correct emails, reports and posts

Accurate and up to date
The rules follow major dictionaries and style guides: Merriam-Webster, the Cambridge Dictionary, Oxford Learner's Dictionaries, the Chicago Manual of Style and the AP Stylebook, with Purdue OWL and APA Style on some pages. Where American and British English differ, or where the style guides disagree, the app says so.

Common Grammar Mistakes is an independent study aid. It is not affiliated with any dictionary publisher, style guide or exam board.

Recent changes:
Completely rewritten: 59 clear lessons on the English mistakes people make most — confusing words, pronouns, agreement, verbs, modifiers, sentence structure, punctuation and spelling — with correct and incorrect examples, memory tips and quizzes. Explanations now in 8 languages: English, Spanish, Portuguese, French, German, Arabic, Hindi and Indonesian.