AI Grammar Checker for ESL & Non-Native English Writers
Diglot is purpose-built for ESL and non-native English writers. It catches the L1-specific patterns generic checkers miss — missing articles, copula drops, false cognates, and translated-sentence rhythm — while you draft, so you ship clean English without copy-pasting between Grammarly, LanguageTool, and your translator.
Generic grammar checkers were trained on native-English writing, so they flag awkwardness but rarely explain why a non-native sentence reads wrong. Diglot is calibrated against L1-transfer patterns — missing articles in Methods sections, copula drops in academic English, false cognates from Spanish or French, and topic-comment word order from Korean and Japanese.
- Catch L1-specific patterns — article omissions, copula drops, tense shifts, false cognates
- Get corrections explained with the native-language reason, not just a generic "this is wrong"
- Run grammar, paraphrase, and translation in the same document — no copy-pasting between tools
What makes a grammar checker built for ESL writers different
Generic grammar checkers were trained on native-English writing, so they flag awkwardness but rarely explain why a non-native sentence reads wrong. Diglot is calibrated against L1-transfer patterns — missing articles in Methods sections, copula drops in academic English, false cognates from Spanish or French, and topic-comment word order from Korean and Japanese.
Korean writers get article-omission corrections explained against Korean grammar; Spanish writers get false-cognate alerts against their L1. Each fix carries the native-language reason — so revisions compound across drafts instead of starting from scratch every paper.
Detection thresholds are tuned per L1 — stricter article-checking for Korean, Japanese, Chinese, Russian (languages without articles); collocation-aware for Spanish and Portuguese false cognates; word-order checks for Arabic and German.
Grammar fix, paraphrase, translation, and originality verification share the same document context. Generic checkers force you between tabs — Diglot keeps your bilingual draft anchored in view while you polish.
How this workflow works
Move from bilingual rough ideas to polished English in one calm flow instead of stitching together separate tools.
Draft naturally first
Write your paragraph without stopping for every small error or awkward phrase.
Scan inline issues fast
Diglot marks spelling, grammar, punctuation, capitalization, and style issues directly in the editor.
Fix what matters most
Accept one suggestion, ignore a rule, or correct multiple issues at once without losing your place in the draft.
Use grammar as part of revision
Turn grammar review into a drafting step instead of a separate proofreading session at the very end.
What you can do with Diglot
Use this workflow to move from bilingual drafts to cleaner English output without breaking your editing flow across separate tools.
One calm path from rough idea to final English
Diglot keeps drafting, translation, grammar review, and rewriting inside the same workspace so you do not have to move text across disconnected tools.
- Spelling, grammar, punctuation, style
- Colored underline categories
- Popover actions on click
Grammar review is embedded in the editor rather than treated as a separate proofing destination.
- Spelling, grammar, punctuation, style
- Colored underline categories
The UI is built around quick, low-friction decisions while you are still drafting.
- Accept or ignore one issue
- Correct all in bulk
What this module includes
The module is not just one button. It is a focused part of the Diglot workspace with real writing actions, review controls, and context-aware output.
Inline issue detection
Grammar review is embedded in the editor rather than treated as a separate proofing destination.
- Spelling, grammar, punctuation, style
- Colored underline categories
- Popover actions on click
Fast correction flow
The UI is built around quick, low-friction decisions while you are still drafting.
- Accept or ignore one issue
- Correct all in bulk
- Add words to a custom dictionary
Explain only when needed
Rule-based checks stay fast and cheap, while AI explanations remain optional.
- LanguageTool as the main engine
- Explain with AI on demand
- Ignore rules that do not fit your context
Who this is built for
Diglot works best when English is your output language but not always your thinking language.
International students
Move from rough documents to cleaner English submissions with structure, paraphrasing, grammar review, and originality checks in one place.
Researchers and graduate writers
Keep academic structure, wording quality, and originality in one workflow when your final output needs to sound precise and credible.
Multilingual professionals
Write faster for work without sounding translated. Diglot helps you refine tone, clarity, and confidence before you hit send.
Why trust this workflow
This page is written for non-native English speakers and reviewed against the current Diglot workflow, not against a generic AI copy template.
Built around real bilingual writing tasks
The guidance on this page reflects how Diglot handles drafting, translation, grammar review, paraphrasing, and originality checks inside one editor.
Written for people who think in one language and deliver in English
Examples, copy, and workflow steps are shaped for students, professionals, and creators who need clearer English output without losing meaning.
Reviewed by Diglot Editorial Team
Last reviewed on May 22, 2026. We update these landing pages when the workflow, module behavior, or recommended writing path changes.
Frequently asked questions
Everything you need to know before getting started.
Is this a free online grammar checker?
Yes — Diglot has a free plan with core grammar checking, paraphrasing, and translation in one editor. Free includes L1-aware corrections for the top six L1s (Korean, Chinese, Japanese, Arabic, Spanish, Russian). Spark ($19/month) and Pro ($29/month) unlock higher word quotas, larger document sizes, and premium model tiers for more accurate corrections.
Can it fix both grammar and spelling?
Yes — grammar, spelling, punctuation, capitalization, sentence clarity, and tone all check inside one pass. Unlike split tools where you have to switch between a spell checker and a separate grammar checker, Diglot surfaces every error category in the same inline review — and explains corrections in plain language, including the L1 reason when relevant.
Is it good for non-native English speakers?
Yes — Diglot is built for non-native English speakers writing in English. The checker recognizes patterns generic tools treat as random "errors": article omissions from Korean, Japanese, Chinese, and Russian L1s; preposition errors from Spanish, German, and French; tense-marker drops from Mandarin; topic-comment word order from Korean and Japanese. Each fix is explained in your L1 context.
Can I use it during drafting instead of after writing?
Yes — Diglot works best as you draft, not as a post-write proofreading layer. Corrections surface inline as you type, the paraphraser sits next to your cursor, and the translator anchors your L1 source on screen the whole time. This means you fix patterns as they appear instead of accumulating them across an 8,000-word draft you then have to rebuild paragraph-by-paragraph.
Does it catch ESL-specific grammar mistakes?
Yes — that is the point. Diglot maintains an L1-transfer-pattern database for each supported language: Korean -고/-며 connector chains producing English comma splices, Japanese topic markers becoming awkward English subjects, Chinese aspect markers (le, guo, zhe) mapping to wrong English tenses, Arabic definite-article overuse, Spanish subjunctive overcorrection. Generic checkers treat each as a one-off — Diglot recognizes the pattern.
Can I combine grammar checking with translation and paraphrasing?
Yes — all four core tools (grammar checker, paraphraser, AI translator, originality verifier) share the same document context inside Diglot. Translate a paragraph from Korean or Spanish, run a grammar pass on the English result, then paraphrase any awkward sentences without losing the surrounding draft. Generic stacks force four browser tabs and four copy-pastes — Diglot keeps it in one editor.
See what each Diglot workflow includes
Explore the writing tasks covered by every Diglot workflow before you jump into related guides and deeper comparisons.
Draft, refine, and rewrite English with AI support built for non-native speakers.
Translate, compare, and edit multilingual text in one writing workflow.
Catch grammar, spelling, and punctuation issues while you write in English.
Rewrite sentences, improve fluency, and keep your original meaning clear.
Scan content for overlap and protect originality before submission or publishing.
Start from ready-made structures for essays, emails, reports, and proposals.
Cryptographically signed proof you wrote your own text — defends against false AI-flag accusations.
Grammar Checker for speakers of:
Diglot's checker models L1-to-English transfer patterns for each language family. Pick yours for the patterns we specifically address.
Use Diglot's AI grammar checker to fix grammar, punctuation, spelling, and clarity issues while you write in English.
Writing in English when it's not your first language is hard — but not because your ideas are weak. Here are 7 practical strategies to write faster, clearer, and more confidently.
Write in your language,
publish in English
Move from rough bilingual drafts to clearer English in one connected writing workflow.
An AI grammar checker for non-native English speakers needs to do more than find typos. The hard cases for ESL writers aren't spelling mistakes — they're the L1-transfer patterns that pass standard checkers as "grammatical English" but read as obviously non-native to a journal reviewer or a hiring manager. A Korean writer drops "the" in front of specific nouns because Korean has no article system. A Chinese writer flattens English tense because Mandarin doesn't inflect verbs. A Spanish writer substitutes "actually" for "actualmente" without realizing the false cognate flips the meaning. A Russian writer chains long subordinate clauses with reflexive participles because Russian academic style rewards length. Each pattern is invisible to a generic checker calibrated against native-English baselines — and each is sharply visible to a reader who decides whether your paper, email, or proposal gets the response you want. Diglot is the only grammar checker explicitly built around these L1-transfer patterns. The corrector maintains a per-L1 database of contrastive linguistic patterns drawn from published ESL research and live error corpora, then explains each fix with the L1 reason — so revisions compound across drafts rather than restarting on every document. Diglot also keeps grammar checking, AI translation, paraphrasing, and originality verification inside the same editor, so your bilingual workflow stops requiring four browser tabs and four copy-pastes. The result: writers who think in Korean, Chinese, Japanese, Arabic, Spanish, or Russian can publish English that reads as if a native-English colleague edited it, without the round-trip through three competing AI tools.
