Exploring the Limitations and Challenges of Grammar Checkers

May 6, 2024

Written By: author image Michael Steiner Reviewed By: Adir Izhaick

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These days, grammar checkers such as Grammarly and Ranx.ai have become ubiquitous tools for writers, students, and professionals aiming to polish their prose. While these applications offer significant assistance, just like any tools, they come with limitations.

Here, we’ll look into the inherent challenges and inaccuracies that these kinds of tools face. I’ll provide you with a detailed exploration of their performance in various linguistic contexts.

Utilizing Grammarly to Correct Grammatical Errors

Grammarly is one of the most renowned grammar-checking tools available. Although it is not flawless, it boasts one of the highest efficiency rates for detecting grammatical errors, making it a favored choice for addressing such issues.

I’ve personally tried this tool, and it consistently detects both major and minor grammar issues in the content of my pages.


Checking for grammar issues with Grammarly

Using Ranx.ai’s Writing Assessment Tool for Checking Grammar

Similar to Grammarly, Ranx.ai’s Writing Assessment tool also features a grammar-checking capability that helps identify grammatical errors on your web pages. Simply enter the URL of your page and click the “Assess Quality” button to initiate the scan.

Here’s a screenshot of a page I scanned using this tool:

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Ranx.ai’s Writing Assessment tool

In just a few minutes—or even seconds—I received a comprehensive report. This report included the page’s word count, readability scores, insights on readability, tone of voice, and grammar issues.

For grammar issues, the tool lists all detected errors along with suggested corrections.

Take a look at this example:


Grammar Issues from Ranx.ai’s Writing Quality Assessment report

Please note that these grammar issues are identified through automated checks, which may not always be perfectly accurate. Therefore, it’s important to review each suggestion carefully.

So how did it turn out? Generally, most of the content items scanned were found to contain errors, demonstrating the tool’s effectiveness in detecting grammatical issues that might otherwise be overlooked, thereby facilitating necessary corrections.

The Mechanisms Behind the Scenes

Grammar checkers rely on complex algorithms and large linguistic databases to function. They analyze text based on predefined grammar rules and statistical norms. However, the intricacies of human language often escape these algorithmic confines.

Limitations of Current Technologies

Grammar checkers are constrained by the underlying technologies that power them, which, despite advances, still exhibit notable limitations. These limitations hinder their ability to fully grasp the complexities of human language, leading to inconsistencies and errors in grammar correction.

Statistical Analysis

Statistical methods in grammar checkers analyze large datasets to predict grammatical correctness. However, they struggle with linguistic nuances and unusual sentence constructions, often missing context-specific errors or applying generic rules too rigidly, which can overlook the writer’s intent.

Rule-Based Systems

Rule-based systems operate on a fixed set of predefined grammar rules. While reliable for common errors, they lack flexibility and adaptability, struggling with evolving language usage, idiomatic expressions, and stylistically complex constructs, which can lead to incorrect suggestions or missed errors.


The Paradox of Grammar Checkers

Grammar checkers have evolved significantly since their inception. However, the core issues of false positives and false negatives remain largely unresolved.

False Positives: The Unintended Consequences

One of the most significant challenges faced by grammar checkers is the issue of false positives. This occurs when the software incorrectly flags correct sentences as erroneous, leading to unnecessary confusion for the writer.


Here are some of the most common false positives that are detected by these tools:

Comma Usage

Many grammar checkers struggle with the contextual nature of commas, often suggesting unnecessary additions or omissions.

For example, if the original sentence is “Let’s eat grandma!” and the grammar checker suggestion was “Let’s eat, grandma!”

While this example humorously highlights the importance of commas for clarity, some grammar checkers may unnecessarily add commas in simpler sentences, disrupting the flow.


Starting sentences with conjunctions such as “and” or “but” is widely accepted in modern writing, yet many grammar checkers cling to outdated rules that flag these as errors. This can unnecessarily restrict writers’ stylistic choices and misrepresent the flexibility of contemporary grammar standards.

Let’s say the original sentence is “And then I realized I had left my keys at home.” and the grammar checker suggestion was “Then I realized I had left my keys at home.”

Starting a sentence with “And” is often stylistically valid, especially in narrative writing. However, grammar checkers sometimes flag this as incorrect due to outdated stylistic rules.

Proper Nouns

Unconventional or newly coined proper nouns frequently confuse grammar checkers, which may suggest corrections that alter intended meanings. This issue is particularly prevalent in texts involving brand names, specialized terminology, or cultural references that are not widely recognized.

For instance, the original sentence is “I recently bought an iPhone.” while the grammar checker suggestion was “I recently bought a phone.”

Some grammar checkers might not recognize “iPhone” as a proper noun and may suggest changing it to “phone,” altering the specific meaning and factual accuracy of the sentence.

False Negatives: Errors Missed

Despite their advanced algorithms, grammar checkers often overlook certain errors, particularly when these mistakes involve complex aspects of language usage. These false negatives can compromise the accuracy and integrity of written work, especially in nuanced or context-specific scenarios:


Grammar checkers struggle with homonyms—words that sound alike but have different meanings or spellings, such as:
• Their
• There
• They’re

These tools frequently fail to detect misuse within the context, leading to unnoticed errors that can alter the intended meaning of a sentence.

Let’s say the original sentence with error is “They went there car.” but there’s a chance that the some grammar checkers will have no correction suggested.

The correct word should be “their” instead of “there.” However, since “there” is also a correctly spelled word, grammar checkers often miss this kind of contextual spelling error.

Contextual Spelling Errors

Words that are spelled correctly but used inappropriately in context often elude detection by grammar checkers. For instance, “accept” versus “except” might be technically correct in spelling, but their misuse can significantly change the message, and yet, these errors typically pass unchecked.

For example, the original sentence with error is “I love eating desert after dinner.” but the grammar checker output didn’t suggest any corrections.

The word “desert” should be “dessert,” referring to a sweet course after a meal. Despite the spelling of “desert” being correct for a different meaning (a barren area of land), it is contextually incorrect here, that might overlooked by grammar checkers.

Understanding the Imperfections

While grammar checkers are valuable tools for general text improvement, they are not infallible. Writers should use these tools as aids, not arbiters, of grammatical accuracy.

Understanding the limitations and operating principles of grammar checkers can empower users to make more informed decisions about when and how to use these tools effectively:

User Awareness: It is crucial for you to remain critically engaged with the feedback provided by grammar checkers.

Tool Improvement: Ongoing development and refinement of algorithms will enhance the accuracy and reliability of these tools.

Balanced Integration: Combining automated feedback with human revision processes ensures a higher quality of writing.

The Bottom Line

Grammar checkers like Grammarly and Ranx.ai are useful for basic error correction and proofreading. However, it’s important to remember that you should not rely solely on them for comprehensive grammar and style management.

Although these tools are not 100% accurate in correcting grammar, it’s still beneficial to use them. They provide an additional layer of grammar checking, which ultimately helps improve your content by identifying issues you might have otherwise overlooked.

Awareness of their limitations and judicious use in combination with careful human editing remains the best strategy for achieving clear, accurate, and expressive writing.

If you’re ready to explore our Writing Assessment tool, feel free to create a Ranx.ai account to get started!

About the Author
Michael Steiner

SEO Specialist

Over the years, I served key roles in several sectors and industries, including online gaming/gambling, e-commerce, fintech and forex in broad international markets.
These experiences include:

  • Setting up and managing the SEO department at 888
  • Founding and managing the Trafix agency –  Involved with SEO technologies development and targeted traffic streaming for gaming sites.
  • Serving as SEO Team Leader at Adgency – one of the largest marketing agencies at Playtech.
  • SEO Team Leader at William Hill Online.