Understanding mistakes in written language

This page helps teachers understand the different kinds of mistake that learners make when writing in the English language.


Learning a language involves becoming proficient in the four skills of speaking, listening, reading and writing. Mistakes are an inevitable part of this process and neither the teacher nor the student should become fixated on them.

It is useful for both, however, to have an understanding of the variety of typical errors in written English, since these are the most amenable to correction. Written errors can be categorized as errors of mechanics, grammar and usage.

Mechanical mistakes

Mechanical mistakes are those of spelling (including capitalisation) and punctuation (including apostrophes). Everyone who writes in English makes such mistakes, whether native speaker or ESL student.

In many cases mechanical errors are the consequence of quick writing where the focus is on the content rather than the form. Although English spelling is difficult, it is possible with diligent use of a dictionary and/or computer spellcheck for every writer to eradicate all or almost all of the spelling mistakes in a piece of writing.

As far as punctuation is concerned, there are a few occasions when a non-native speaker is more prone to make a mistake than a native speaker. For example, German requires a comma between main and subordinate clauses, whereas English doesn't.

The most common punctuation mistakes, however, arise when the student does not correctly end a sentence (producing either a fragment An incomplete sentence; often a stand-alone dependent clause. For example:

- Because I was tired.
or a run-on A sentence containing two independent clauses, typically connected with a comma. For example:

- I love Paris, it's a beautiful city.
.) These are typical of immature writers who do not understand the concept of a sentence.

Such errors are neither more nor less likely to be found in an ESL student's work. The same goes for the incorrect inclusion, omission or faulty placement of apostrophes.

@@@ Mechanical errors seldom interfere with comprehension, but can reflect negatively on the writer, particularly in formal/academic settings. ~~~ Mainstream teachers can be sure that ESL teachers will have identified students who make a large number of mechanical errors and will be working with those students to rectify the problem.

Mainstream teachers are probably best advised not to make a big issue of general mechanical errors. But it is not unreasonable for them to insist on the correct spelling of the key subject-specific words that are currently being learned by the whole class. For example: photosynthesis, deforestation, hypothesis, etc.

These words will no doubt have been written on the board and will appear in class and homework worksheets.

Grammar mistakes

Grammar mistakes rarely occur in native speakers' writing but very commonly do in the work of less proficient ESL students, whose mother-tongue "interferes" with the production of correct English.

ESL students make numerous mistakes in the use of verbs (for example, incorrect tense choice, incorrect tense form, tense shift), the articles (a/an, the - particularly Asian students in whose languages these words do not exist), and word order.

A typical interference mistake of a German learner of English is: "I am here since two weeks " instead of "I have been here for two weeks ". A further example is: "I tell you tomorrow" instead of "I'll tell you tomorrow. "

Grammar mistakes in writing occasionally disrupt comprehension, but usually they do not. The student who writes "I putted beaker on tripod", for example, will have conveyed his meaning perfectly intelligibly.

There is no clear evidence that ESL students benefit from correction of grammar mistakes, even in contexts where the explicit focus of the teaching is grammar. Therefore the mainstream teacher is advised not to make a big fuss about such mistakes in the student's written assignments. Such mistakes will disappear as the student's interlanguage Interlanguage is the term for the student's implicit English grammar knowledge as it develops through the years of learning the language.

Interlanguage is often heavily influenced by the mother tongue, in a process called interference.
begins to approach the intuitive grammatical knowledge of a native speaker.

On the other hand, there is no reason why it should not be made clear to ESL students who are writing an account of a historical event, for example, that they are expected to write verbs in the past simple tense. And it is helpful if the history teacher identifies these mistakes.

Usage mistakes

A usage mistake is a word or a string of words in a sentence that is grammatical There is a gray area where usage shades into grammar, such as in the choice of prepositions.

For example: "I'm good at chess" is standard English. Is "I'm good in chess" therefore a grammar error or a usage error? There is no definitive answer.
, but not usual in standard English. Hence native speakers rarely make usage mistakes, but ESL students very often do.

Such mistakes frequently occur in ESL students' work when they look up a word in their own language and select the wrong English equivalent for the meaning they wish to express.

Conversely, failure to use the dictionary can result in the false friends usage mistake. For example, kontollieren in German means to check (over) , so the following problem in the German student's writing is not surprising: "It is important to control (i.e. check) the results carefully."

Faulty usage in larger passages of writing is often the consequence of the attempt to render word-for-word into English the mental or written version that the ESL student has in the native tongue. It is such mistakes in an ESL student's work that can make it difficult to understand what meaning is being conveyed.

@@ Usage mistakes, like grammar mistakes, are not particularly susceptible to eradication by direct correction. ~~ And like grammar mistakes they will eventually disappear, particularly if the student reads extensively in English.

However, the mainstream teacher is advised to alert an ESL student to usage mistakes in the way she conveys a meaning that is common or integral to the subject. For example: "The dictator was thrown over (overthrown) in a people's revolt" or "We observed (examined) the slide for the presence of salt".

Error examples

Click the button below for examples of the mistakes discussed above.

The following mistakes were made by beginning ESL students. The task was to write a summary and reflection on the life of Joseph Merrick, who came to be known as the Elephant Man.


He had loose clothes so nobody can see his body.
He didn't talked so clearly. When he lied down his neck breaked.
Many people was afraid of him.
But Dr Treves helped him having an easier life.


He had 2 operation to take out the lumps of skin.
His left hand was normal and right hand was size of elephant's trunk.
He took off his glasses and put it on the table.


word order
The guy that took care of him gave him in the hospital his own room.
reported speech
I want to know how did Joseph Merrick make such a beautiful model.
sentence fragments
Because his right leg was like an elephant's.
run-on sentences
August 5 in Lee Street Joseph Merrick was born when he was born his body was terrible.


word choice
The operator cut skin from his head.
Merrick went asleep.


He's name was Joseph Merrick. On his back their was a ball of skin.
His left hand was like a 10 year old girls hand.
He couldn't walk like a Human.

More important criteria

It is quite possible for an ESL student to turn in a piece of written work that contains few mistakes of mechanics, grammar or usage, but is a long way from meriting a good grade.

This is usually because the student has not understood or complied with the writing task, has given no thought to organization and structure, has made no effort to string sentences together in a coherent way, has plagiarized, and so on.

All of these are more important criteria in producing a piece of work that merits a high grade.

In fact, @ most of the basic mistakes of mechanics, grammar and usage will disappear automatically as the ESL student becomes more proficient in English. ~So mainstream teachers need not focus too much attention on them.

Instead, it is a primary task of the mainstream teacher to help ESL students (indeed all students) to improve in the more fundamental aspects of writing well, as listed in the previous paragraph. This applies particularly to subject-specific genres such as lab reports, persuasive essays, critical assessments of historical events, etc.

Further reading

There are many examples of typical English-learner mistakes (including mistakes in spoken language) in the explanation of language words for non-language teachers .

You may also wish to look at the page written for learners about understanding writing mistakes.

There is a section of the site that contains analyses of learner errors. The starting page in that section is introduction to error analysis and correction.


Mistakes are an inevitable, even necessary, aspect of learning a new language. ESL students should not be afraid to make mistakes. And teachers should generally give feedback only on mistakes that impede comprehension.