LanguageTool

LanguageTool is an AI-powered writing and proofreading platform designed to help users improve grammar, spelling, punctuation, style, tone, clarity, and overall writing quality. It is used by students, writers, professionals, businesses, editors, translators, and teams that want accurate and polished communication across multiple languages.

LanguageTool began in 2003 as an open-source project and has developed into a commercial writing assistant while continuing to maintain an open-source core. The platform is built by linguistic professionals and machine-learning specialists and focuses heavily on multilingual writing support.

Unlike tools that mainly generate content from scratch, LanguageTool is primarily an AI editing and proofreading platform. Its main purpose is to improve text that a user has already written. The system analyzes the context of sentences and provides suggestions designed to correct mistakes and make writing clearer, more professional, and more consistent.

One of LanguageTool’s main features is its grammar checker. It identifies grammatical problems such as incorrect word order, verb errors, agreement issues, missing words, and other context-dependent mistakes. The system can distinguish between different possible meanings of words and provide suggestions according to the sentence’s context.

The platform also includes a spell checker that detects misspelled words, incorrect capitalization, and other spelling problems. It can recognize names, technical terms, acronyms, and other vocabulary through its personal and team dictionary features.

LanguageTool’s punctuation checker identifies missing, unnecessary, or incorrectly placed punctuation. Its advanced checking can distinguish between optional and required punctuation in different contexts, which is particularly useful for longer professional and academic documents.

Another major feature is style checking. LanguageTool can identify repetitive wording, unnecessary words, informal phrasing, awkward constructions, and other issues that may reduce the clarity or professionalism of written communication.

The platform also analyzes tone and formality. Users can receive suggestions intended to make text more professional, concise, friendly, or suitable for a particular communication context. This makes the tool useful for emails, reports, business documents, academic writing, and online communication.

LanguageTool provides an AI-powered paraphrasing tool that can rewrite sentences while preserving their intended meaning. Users can adjust wording to make sentences simpler, shorter, more formal, or more fluid. Premium users receive unlimited sentence paraphrasing, while the free version has a limited daily allowance.

Another useful capability is the Personal Dictionary. Users can add names, specialized vocabulary, industry terminology, product names, or other words that they do not want LanguageTool to flag as spelling mistakes.

For organizations, LanguageTool provides a Team Dictionary and Team Style Guide. Teams can establish common terminology, preferred wording, and style rules so that employees maintain consistent communication across documents, customer messages, reports, and other written materials.

LanguageTool also includes writing statistics. The platform can track information such as the languages users write in, errors detected, and suggestions applied. These statistics can help users understand their writing habits and monitor improvements over time.

The LanguageTool Editor provides a focused environment where users can write, edit, save, and review documents. It is available through the web as well as dedicated applications for Windows and macOS. Users can also import Word documents and retain formatting while editing.

LanguageTool is designed to work directly where people write. Its browser extensions support popular browsers including Chrome, Edge, Firefox, Safari, and Opera. Users can receive suggestions directly in websites and web applications instead of constantly copying text into a separate editor.

The platform also offers integrations with Google Docs, Microsoft Word, Apple Pages, and LibreOffice. This allows users to check and correct documents inside familiar office and productivity environments.

For email communication, LanguageTool integrates with platforms and applications including Gmail, Apple Mail, Outlook, and Thunderbird. This is useful for professionals who need to review business emails before sending them.

LanguageTool also provides dedicated desktop applications. Its Windows application can check text in supported desktop programs, while the macOS application works with applications such as Mail, Pages, Notes, Messages, and Slack.

For developers and software companies, LanguageTool provides a Proofreading API. The API can be integrated into software products and websites that require grammar, spelling, punctuation, or style checking. It returns structured JSON data and can automatically detect the language of submitted text.

The API supports multiple languages and can be configured with specific grammar and style rules. Developers can also access Personal Dictionary functionality through the API.

LanguageTool provides both cloud and self-hosted options for its language technology. Its open-source foundation allows users and developers to operate their own LanguageTool server, giving organizations greater control over deployment and data.

Privacy is an important part of the platform’s positioning. LanguageTool states that its browser add-on generally does not store the text users type into websites. Its API infrastructure is hosted in Germany, and the company promotes GDPR-compliant services.

LanguageTool is also used by organizations that need consistent professional communication. The Business offering provides user management, centralized style rules, team dictionaries, and other capabilities intended to maintain a common communication standard across organizations.

One of LanguageTool’s biggest advantages is its multilingual capability. The platform supports more than 30 languages and dialects, with stronger Premium checking available for English, German, French, Spanish, Dutch, Polish, and Portuguese.

English users can select multiple regional varieties, including American, British, Canadian, Australian, New Zealand, and South African English. German users can work with Austrian, German, and Swiss variants, while Portuguese includes regional varieties such as Angola, Brazil, Mozambique, and Portugal.

The platform also supports less commonly covered languages and dialects, including Asturian, Belarusian, Breton, Crimean Tatar, Esperanto, Galician, Irish, Khmer, Persian, Tagalog, Tamil, and Ukrainian.

LanguageTool is particularly valuable for people who write in multiple languages because it can automatically detect the language being used and provide relevant suggestions. This is one of the main areas where it differentiates itself from English-first writing assistants.

Another strength is its open-source heritage. LanguageTool’s core technology remains available as open-source software, allowing developers to inspect the technology, contribute improvements, and host their own LanguageTool server.

The platform is also widely available across devices and environments. Users can access it through the web editor, browser extensions, desktop applications, mobile applications, office plugins, email integrations, and API-based implementations.

LanguageTool reports more than 2 million active browser-add-on installations, more than 150 companies using its business products, and more than 20 million texts improved every day. These figures are company-reported platform statistics.

The service has built a strong presence among professional writers, businesses, students, and international users. Its multilingual focus makes it especially useful for people who frequently move between different languages or regional varieties of the same language.

LanguageTool should be considered primarily an AI editing and proofreading platform rather than a full AI content-generation system. It can rewrite and paraphrase existing sentences, but its core value is helping people improve their own writing.

The platform also emphasizes privacy and user control. Users can maintain personal dictionaries, configure writing preferences, and choose between cloud-based services and self-hosted options where available.

For teams, the combination of a shared dictionary and centralized style guide can help prevent inconsistent terminology. This is useful for companies with specific product names, technical language, brand terminology, or communication standards.

LanguageTool is suitable for a wide range of writing tasks including academic writing, professional communication, business documents, emails, articles, reports, proofreading, editing, and multilingual communication.

Its main limitation is that it is not designed to replace a full content-marketing platform. Users looking for extensive long-form content generation, AI image generation, video production, or automated SEO campaigns may need other tools.

LanguageTool is strongest when the goal is to make existing text more accurate, professional, readable, consistent, and natural. Its combination of multilingual support, browser and office integrations, AI paraphrasing, business style controls, open-source technology, and developer APIs makes it one of the more versatile writing-assistance platforms.

Pricing

LanguageTool currently offers a free version and several Premium billing options.

Basic

Free

• Basic grammar checking
• Basic spelling checking
• Basic punctuation and style checking
• Up to 10,000 characters per text
• 3 AI-powered paraphrased sentences per day
• Browser extensions
• Basic writing assistance

Premium

€19.90/month

€39.90/quarter

€59.89/year

€99.90/2 years

Premium includes:

• Enhanced grammar checking
• Advanced punctuation and style checking
• More than 20,000 additional checks for supported premium languages
• Up to 150,000 characters per text field
• Unlimited AI sentence paraphrasing
• Personal Style Guide
• Personal Dictionary
• Advanced writing suggestions
• Premium browser and application features

Team

€56.90 per user/year

• Premium access for team members
• Shared Team Style Guide
• Team Dictionary
• User management
• Centralized writing standards
• Up to 20 users

Business

Custom pricing

• Business-focused deployment
• Team administration
• GDPR-compliant business solutions
• Advanced organization controls
• Custom requirements

LanguageTool subscriptions are automatically renewed according to the selected billing period, and users can cancel before the next renewal.

Review

LanguageTool is a strong writing assistant for users who prioritize grammar, spelling, punctuation, style, and multilingual proofreading. Its biggest advantage is that it works across many languages and applications rather than being restricted to a single editor.

The free version is useful for basic proofreading, while Premium adds substantially more advanced checking and unlimited AI paraphrasing. The price of the annual Premium plan is also relatively competitive compared with several major writing assistants.

One of LanguageTool’s strongest features is its extensive language coverage. It supports more than 30 languages and dialects, including several languages that are not always well supported by competing writing assistants.

Its browser and office integrations are also valuable. Users can work inside Chrome, Firefox, Edge, Google Docs, Microsoft Word, Apple Pages, LibreOffice, Gmail, Outlook, and other supported applications without repeatedly moving text between services.

LanguageTool also scores well for privacy-conscious users because its company emphasizes GDPR compliance and offers an open-source version that can be self-hosted.

Third-party customer feedback is generally positive. Capterra currently gives LanguageTool 4.1/5 from 50 reviews, with 4.3/5 for ease of use and 3.5/5 for customer service. Reviewers frequently praise its grammar and spelling correction, multilingual capabilities, customization, ease of use, and privacy advantages.

Some reviewers have reported that AI-based suggestions can occasionally be unreliable, particularly when switching between languages. Other feedback indicates that LanguageTool does not always appear in every writing field as consistently as some competing browser-based assistants.

Another consideration is that the strongest advanced checks are concentrated in a smaller group of premium languages: English, German, French, Spanish, Dutch, Polish, and Portuguese. Other languages receive support but may not have the same depth of advanced checking.

LanguageTool is best suited to writers, students, professionals, editors, businesses, multilingual users, translators, and teams that need reliable proofreading and consistent written communication.