Grammar checkers, often called AI proofreaders, sentence correctors, grammar correctors, or sentence checkers, identify grammar errors and provide suggestions to improve the user's writing. These proofreading software help students and working professionals write emails, presentations, and research papers. They are especially helpful to those whose native language is not English but need to write in English for school or work. In this blog post, I introduce the three best grammar checkers for non-native speakers of English.

Summary

In short, I would pick these three grammar checkers for non-native English speakers

  1. Pcanpi
  2. Quillbot
  3. Grammarly

Background

When I was working for Amazon as a Senior Product Manager in 2016, I had to write a lot. My colleagues with the same job title used to joke about one of Amazon’s Leadership Principles that read “leaders are right a lot,” which we read as “leaders write a lot.”

Amazon was notorious for requiring product managers to write six-pagers to articulate what needed to be built, and I had first-hand experience of this. Executives and managers at the company were obsessed with reviewing papers for the quality of writing. My former boss, who had been a journalist in the past, once put corrections all over my paper in red. One of my colleagues also once gave harsh feedback to my manager, saying my writing was “choppy.” It took weeks for me to complete a proposal, as I had to rewrite it dozens of times before it was presented to a VP. In one meeting, a VP read a part of my paper out loud and pointed out a phrase that was not clear to her. I believe anyone whose native language is not English could imagine how terrifying that experience was.

I tried many grammar checkers back then, but none of them were really helpful. I was so frustrated by this because people all over the world were talking about AI and machine learning, and yet no one had developed software that could solve my problem.

Now, however, the technology of grammar checking software has gotten significantly better, and there are several I would recommend to non-native speakers of English like myself.

How I chose them

I tested the seven grammar checkers below:

  1. Grammarly
  2. Quillbot
  3. ProWritingAid
  4. Ginger
  5. Trinka
  6. Wordvice
  7. Pcanpi

On each grammar checker, I typed in these five sentences which demonstrate some common mistakes that non-native English speakers make:

  1. Do you have exercise?
  2. We don’t go to California in a long time.
  3. Look at the below chart.
  4. I had no choice but to go bank.
  5. He recommended the other one with cheaper price.

Then, I talked to a few of my friends who currently work or study in the US as non-native speakers of English and got their input.

Below are the details of my evaluation

1. Grammarly

Grammarly is probably the most well-known grammar checker. It has a beautiful UX and fixes many grammar errors that native speakers of English make. Although it's also a great tool for non-native English speakers, it ignores some common mistakes that they often make. Here are the results of my test:

  1. Do you have exercise? → Do you have exercise? (no change)
  2. We don’t go to California in a long time. → We don’t go to California for a long time.
  3. Look at the below chart. → Look at the below chart. (no change)
  4. I had no choice but to go bank. → I had no choice but to go bank. (no change)
  5. He recommended the other one with cheaper price. → He recommended the other one at a lower price.

Grammarly was unable to correct these sentences. However, I did like the way Grammarly suggests an alternative word in a given context.

2. Quillbot

Quillbot has both a grammar checker and a paraphraser. I tested them, and both were good. I found their paraphraser better because it rephrased all five sentences to make them sound more natural. Here are the results of Quillbot’s paraphraser:

  1. Do you have exercise? → Do you get any exercise?
  2. We don’t go to California in a long time. → We haven't been to California in quite some time.
  3. Look at the below chart. → Take a look at the graph below.
  4. I had no choice but to go bank. → I was forced to go to the bank.
  5. He recommended the other one with cheaper price. → He suggested the other one, which was less expensive.

The only downside of the paraphraser is that it may slightly change the meaning of the original sentence, which can be bad depending on the writer’s intention.

3. ProWritingAid

If I remember correctly, ProWritingAid has been in the market for as long as Grammarly has. When I read posts about top grammar checkers, ProWritingAid had been in and out of these lists, whereas Grammarly had been in every one of them. ProWritingAid is somewhat on par with Grammarly in terms of the quality of their suggestions:

  1. Do you have exercise? → Do you have exercise? (no change)
  2. We don’t go to California in a long time. → We haven’t went to California in a long time.
  3. Look at the below chart. → Look at the below chart. (no change)
  4. I had no choice but to go bank. → I had no choice but to go bank. (no change)
  5. He recommended the other one with cheaper price. → He recommended the other one at a cheaper price.

From testing these sentences, I am not sure whether I would recommend ProWritingAid over other writing assistants for non-native English speakers.

4. Ginger

Ginger also has been around for almost a decade. In terms of its accuracy with grammar checking, it’s similar to ProWritingAid:

  1. Do you have exercise? → Do you have exercise? (no change)
  2. We don’t go to California in a long time. → We don’t go to California in a long time. (no change)
  3. Look at the below chart. → Look at the below chart. (no change)
  4. I had no choice but to go bank. → I had no choice but to go the bank.
  5. He recommended the other one with cheaper price. → He recommended the other one with cheaper price. (no change)

Similar to ProWritingAid, I would not recommend Ginger over other writing assistants for non-native English speakers.

5. Trinka

Trinka is a grammar checker developed by Enago, a human proofreading service. Its grammar checking accuracy is similar to other grammar checkers.

  1. Do you have exercise? → Do you have exercise? (no change)
  2. We don’t go to California in a long time. → We don’t go to California in a long time. (no change)
  3. Look at the below chart. → Look at the chart below.
  4. I had no choice but to go bank. → I had no choice but to go bank. (no change)
  5. He recommended the other one with cheaper price. → He recommended the other one with cheaper price. (no change)

Trinka often ignores grammar mistakes in the test sentences. For this reason, I would not recommend Trinka for non-native English speakers.

6. Wordvice

Wordvice is a grammar-checking software developed by another human proofreading service. Although it tends to make some changes, it does not show a significant difference in its accuracy.

  1. Do you have exercise? → Do you have exercise? (no change)
  2. We don’t go to California in a long time. → We have been to California a long time.
  3. Look at the below chart. → Look at the chart below.
  4. I had no choice but to go bank. → I had no choice but to go to the bank.
  5. He recommended the other one with cheaper price. → He recommended the other one at a cheaper price.

One notable difference is that it often changes the meaning of the original sentence after making edits. For this reason, I would not recommend Wordvice for non-native English speakers.

7. Pcanpi

Many of you may not know of Pcanpi yet because it's relatively new, but it can fix errors that other grammar checkers overlook.

Here are the results of Pcanpi on the five sentences I tested:

  1. Do you have exercise? → Do you exercise?
  2. We don’t go to California in a long time. → We haven't been to California in a long time.
  3. Look at the below chart. → Look at the chart below.
  4. I had no choice but to go bank. → I had no choice but to go to the bank.
  5. He recommended the other one with cheaper price. → He recommended the other one with a cheaper price.

I liked Pcanpi’s suggestions because it made corrections without changing the meaning of the original sentences.

Final thoughts

As you can see from above, no grammar checker is perfect for everyone. A friend of mine told me that she uses both Pcanpi and Grammarly to get the best outcome because there are certain types of mistakes that one catches better than the other. I think other non-native speakers can also try that out to bring out the best of their writing.

If you have trouble with English grammar, come on over to Pcanpi where our AI-powered proofreader will help guide you to the correct grammatical phrases and expressions.

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