LanguageTool
Open-source AI grammar checker for 30+ languages \u2014 privacy-first, multilingual, and GDPR-compliant
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About LanguageTool
LanguageTool is an open-source, AI-powered grammar, spelling, punctuation, and style checker that supports more than 30 languages and 45 dialects \u2014 making it the most linguistically diverse writing assistant available. Originally created in 2003 by Daniel Naber as an open-source project, LanguageTool has grown into a widely used professional writing tool trusted by students, authors, publishers, international business teams, and multilingual professionals who need reliable writing assistance beyond English-only tools.
What truly sets LanguageTool apart is its combination of multilingual depth and privacy-first architecture. Unlike most grammar checkers which store user text on their servers, LanguageTool processes text without retaining it \u2014 a crucial feature for professionals handling sensitive legal, medical, or business content, and a natural fit for the GDPR-conscious European market where the company is based. The tool works seamlessly across Google Docs, Microsoft Word, LibreOffice, all major browsers, Gmail, and social platforms via extension, giving users consistent AI-assisted writing support regardless of where they write.
LanguageTool is the right choice for multilingual writers, European professionals and businesses under GDPR obligations, open-source advocates, academic writers working across multiple languages, and anyone who prioritizes data privacy alongside effective grammar correction \u2014 especially at its highly competitive pricing starting from $4.99/month on a 2-year plan.
Key Features
- Grammar, spelling, punctuation, and style checking across 30+ languages and 45+ dialects
- AI-powered paraphrasing tool for alternative sentence suggestions (Premium)
- Privacy-first architecture — text not stored on servers; GDPR-compliant EU-based processing
- Browser extensions for Chrome, Firefox, Safari, and Edge — works on any website
- Google Docs and Microsoft Word integrations for in-document real-time checking
- LibreOffice and OpenOffice add-in for open-source office suite users
- Personal dictionary for saving custom words, names, and company terminology
- Automatic language detection — no need to manually select source language
- Synonym suggestions by double-clicking any word in the editor
- Open-source core — available on GitHub, with community-contributed rules for all supported languages
Pros
- 30+ languages and 45+ dialects — unmatched multilingual grammar checking coverage
- Privacy-first: text not stored on servers, GDPR-compliant EU-based processing
- Open-source core — transparent, community-contributed rules available on GitHub
- Highly affordable — Premium from $4.99/month on 2-year plan, best value in category
- Works across Google Docs, Word, LibreOffice, all browsers, Gmail, and social platforms
- Automatic language detection — seamlessly handles multilingual documents
- Trusted by publishing houses, academic institutions, and international business teams
Cons
- Free plan limited to 2,000 characters per text field — restrictive for long documents
- AI features (paraphrasing, advanced style) only available on Premium
- Style suggestions less sophisticated than Grammarly Premium for native English writers
- No built-in plagiarism checker or document editor
- Customer support response times reported as slow by some users
Pricing
LanguageTool offers a free plan with basic grammar and spelling checks limited to 2,000 characters per text field \u2014 suitable for short emails and social media posts.
Premium plans unlock 150,000 characters per field, advanced style suggestions, AI-powered paraphrasing, personal dictionaries, and synonym tools. Pricing: $24.90/month (monthly), $69.90/year ($5.83/mo), $49.90/quarter, or $119.80 for 2 years ($4.99/mo) \u2014 making the 2-year plan one of the most affordable premium grammar checkers available.
LanguageTool for Teams (Business) adds team management, centralized billing, API access, and custom dictionaries. Contact LanguageTool through languagetool.org for business pricing.
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Frequently Asked Questions
LanguageTool checks grammar, spelling, punctuation, style, and tone across 30+ languages and 45+ dialects. It detects language automatically and provides context-aware suggestions in real time. Unlike most competitors which focus on English, LanguageTool’s multilingual coverage is its key differentiator — making it the top choice for writers who work in multiple languages.
LanguageTool is developed and hosted in Germany under strict EU/GDPR data protection laws. Crucially, your text is not stored on LanguageTool’s servers after processing — making it a privacy-first choice for professionals handling confidential documents, legal content, or sensitive business communications.
LanguageTool supports 30+ languages and 45+ dialects including English, German, French, Spanish, Portuguese, Italian, Dutch, Polish, Russian, Ukrainian, Chinese, Japanese, and many more. This multilingual depth is unmatched among AI grammar checkers.
The free plan checks up to 2,000 characters per text field with basic grammar and spelling corrections. Premium (from ~$4.99/month on the 2-year plan) raises limits to 150,000 characters per field and adds advanced style suggestions, AI-powered paraphrasing, personal dictionaries, and synonym suggestions.
LanguageTool integrates with Google Docs, Microsoft Word, LibreOffice, OpenOffice, all major web browsers (Chrome, Firefox, Safari, Edge), Gmail, Google Slides, Outlook, WordPress, and social media platforms via browser extension. It also offers an API for developers to integrate into their own applications.
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Compared with LanguageTool
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