How to Write a Research Paper in English: A Guide for Non-native Speakers
Updated: Jul 9, 2021
Table of Contents
Often, a reviewer will unfairly reject a valuable piece of research merely because the author does not write clearly enough. Therefore, I have written this article to help non-native English speakers get their research published, specifically by teaching you how to avoid the most common writing patterns that lead to an automatic rejection.
The first section of this article lays the foundation for subsequent sections by explaining the fundamental components of all sentences written in English. The second section then shows you how to combine and arrange these components to ensure that your sentences are well-structured. The third section offers more specific advice, teaching common pitfalls that you should avoid in your writing. The fourth section provides some tips that you can use to polish your writing during the final round of revision.
Introduction to Sentence Structure
The advice provided in this section will help you understand the components that make up English phrases so that you can write more clearly.
Every English sentence is made up of one or more phrases, and each of these phrases consists of one or more words. Each word belongs to a specific category (these categories are known as word classes or parts of speech). While you do not need to know all the parts of speech to understand this article, you should at least know what nouns and verbs are. Prepositions are also used quite often in the examples in this section.
Moreover, every phrase has a head—the head is the most important word in a phrase since the head determines what type of phrase is being dealt with. For example, if the head of a phrase is a noun, then the entire phrase is a noun phrase. If the head of a phrase is a verb, then the entire phrase is a verb phrase. All other words within a phrase that are not the head are called complements.
Being able to identify different types of phrases and their heads is crucial to writing clearly. Here, you will learn how phrases are put together with the aid of sentence tree diagrams. These diagrams get their name from the fact that they present sentences in a way that resembles (upside-down) trees, as shown below.
Note that the graphics I present here are not exactly as they would appear in a linguistics textbook. I've tried to make it as easy as possible for you to visualize how the most important phrases in a sentence are pieced together while paying less attention to smaller, less significant phrases.
In sentence tree diagrams, phrases and words are connected by lines (“branches”). Individual words are found at the very end of each branch—these are the “leaves,” or, as linguists call them, “terminal nodes.”
Sentence tree diagrams can be confusing. As you continue reading, remember that I have included them here primarily as a visual aid. You do not need to understand how the diagrams are constructed. For the purposes of this article, I will start with a very simple sentence.
S = sentence; NP = noun phrase; VP = verb phrase; N = noun; V = verb
The example sentence above consists of two words. In this case, each word is also a full phrase. Sentences like this one that contain only a noun and a verb are among the simplest that can be written in English. With some exceptions (which almost never appear in academic writing), all sentences written in English must have at least one noun phrase and one verb phrase.
Levels of a Tree Diagram
The basic structure of a tree diagram is as follows. The “S” at the top of the diagram stands for “sentence.” All the diagrams presented in this section will have this “S” at the top, as all the examples are full sentences.
The second level from the top of the tree denotes the phrase type. Most phrases consist of several words (the example given above is an exception). The examples in this section include only three types of phrases: noun phrases (labelled as “NP”), verb phrases (“VP”), and prepositional phrases (“PP”). I did this to keep this article as simple as possible. However, be aware that there are other types of phrases.
The third level of the tree shows the word class that each word belongs to (in the example above, “N” denotes a noun, and “V” denotes a verb). As you will see in later examples, large phrases often contain two or more smaller phrases. Therefore, there can be several steps between the first phrase level of a tree diagram and the word level.
Finally, at the bottom of the branches are the words that make up the sentence. These are always directly linked to the appropriate label. For example, since ate is a verb in the above example, it is directly connected to a “V” label.
A Slightly More Complicated Example
I would like to provide another simple example before beginning an in-depth discussion about sentence patterns. Unlike the previous example, this one contains a phrase within a phrase, as well as a couple of non-head words (i.e., complements).
S = sentence; NP = noun phrase; VP = verb phrase; N = noun; V = verb; P = preposition
In the sentence above, the words an and apple are complements. Even though apple is the head of its own short noun phrase, it is a complement when we consider the entire sentence. As we work our way up the tree, we see that apple is included in the verb phrase "ate an apple." Therefore, the phrase "an apple" is a complement to the verb ate. Meanwhile, the noun I is the subject of the sentence because it comes before the verb.
To summarize, most sentence tree diagrams contain the following components:
Individual words are given at the bottom of the diagram. These are usually grouped into phrases, although you will occasionally find phrases that contain only one word.
One of the words within each phrase is the head of that phrase. The head determines what kind of phrase is being dealt with. For example, if the head of a phrase is a noun, then that entire phrase is a noun phrase.
Any word within a phrase that is not the head is called a complement.
The subject of a sentence (which is almost always a noun phrase) comes before the sentence’s main verb.
Two or more phrases can be grouped into larger phrases.
All sentences in academic writing must, at the very least, contain a subject (noun) and a verb phrase.
Basic Sentence Patterns for Research Writing
Most of the sentences that you write should have the same basic format, which I will describe in this section. The ideal sentence structure for academic writing is illustrated in the simplified diagram below:
This diagram shows the fundamental structure shared by most well-written sentences found in academic literature. As the diagram shows, a basic English sentence has three components:
It starts with a short noun phrase (NP) that serves as the subject.
The subject is immediately followed by a verb that serves as the head of the sentences’ main verb phrase (VP).
Within this verb phrase are one or more complements that can contain all types of words and phrases.
I will now show how you can apply this basic sentence structure to your writing. Notice how each example builds upon the previous one without disrupting the basic pattern.
We’ll begin with a simple six-word sentence: “We allowed the mixture to cool.”
S = sentence; NP = noun phrase; VP = verb phrase; PP = prepositional phrase; N = noun; V = verb; Art = article; P = preposition
This sentence begins with (1) a short noun phrase (the single word we), which is the subject of the sentence. This is immediately followed by (2) the word allowed, which is the head of the sentence’s main verb phrase ("allowed the mixture to cool"). This verb phrase contains (3) a complementary noun phrase that includes an article (the), a noun (mixture), and a prepositional phrase ("to cool").
With this basic sentence in place, we can now decide whether we want to expand upon our sentence to give the reader any extra information. If we decide to add information, we would usually do so by adding complements to the verb phrase, not the subject. Any complements added to the subject must be short, or you'll risk confusing the reader.
In the example below, I have added the complement as a final step to the beginning of the sentence. In a full paper, this would serve as a transitional phrase.
S = sentence; NP = noun phrase; VP = verb phrase; PP = prepositional phrase; N = noun; V = verb; Art = article; P = preposition; Adj = adjective
The subject of the sentence is still the noun we, as it is still the head of the noun phrase at the highest level of the tree. Although this noun phrase is now larger due to the introductory phrase, its position in the tree has not changed.
We might also decide to say something more about the cooling process. For example, we can let the reader know what temperature we let the mixture cool to by adding a new complementary phrase to the end of the sentence. We can also add to our sentence by expanding phrases that we have already written. For instance, to the noun "the mixture," I have added the adjective combined.
These new additions' placements in our sentence are depicted in the diagram below. Now that the sentence is getting fairly complex, I will begin to emphasize new words with red font.
S = sentence; NP = noun phrase; VP = verb phrase; PP = prepositional phrase; N = noun; V = verb; Art = article; P = preposition; Adj = adjective
Notice that none of the additions have altered the basic sentence structure. We still have (1) a short noun phrase at the beginning of the sentence that is headed by the subject. We then have (2) allowed, which is still the head of the sentence’s main verb phrase. This is followed by (3) several complementary phrases.
Most importantly, the head of the main noun phrase (we) is still immediately followed by the head of the main verb phrase (allowed). To reinforce the significance of this, I provide one last example containing over 30 words. Even though the sentence is long, it is easy to follow because the basic pattern has not been broken.
S = sentence; NP = noun phrase; VP = verb phrase; PP = prepositional phrase; N = noun; V = verb; Art = article; P = preposition; Adj = adjective
Once a sentence exceeds 30 words (as in the example above), the writer risks forcing the reader to re-read the sentence. The purpose of the above example is to show that even very complex sentences have the same basic structure as very simple ones.
Of course, the example above is not the only way that this sentence could be written. As a precursor to the next section, I offer three final examples. These sentences are all equally grammatical and convey the same information. However, they are not equally easy to read. The first sentence is the easiest to follow (and, therefore, is the best-written). The third sentence is the most difficult to read.
As a final step, we allowed the combined mixture to cool to room temperature in the laboratory under normal conditions before taking any measurements, following the methodology employed by other researchers.
As a final step, following the methodology employed by other researchers, we allowed the combined mixture to cool to room temperature in the laboratory under normal conditions before taking any measurements.
As a final step, following the methodology employed by other researchers, the combined mixture, in the laboratory under normal conditions, was allowed to cool to room temperature before taking any measurements.
The first sentence—which is the original sentence from the tree diagram above—is not perfect, but it follows the standard structure of an English sentence and, therefore, is unlikely to confuse the reader.
The second sentence breaks one of the rules of the basic sentence structure—namely, a fairly long complement ("following the methodology employed by other researchers") has been placed before the subject (we).
As mentioned earlier, long complements should not be placed before the subject of a sentence—the earlier the subject appears in a sentence, the easier the sentence is to read. Remember, well-written sentences begin with a short noun phrase followed by a verb phrase. While readers can take in a lot of information after the subject and main verb of a sentence have been given, they can handle only minimal amounts of information before these crucial words are introduced. More details about this matter are given in the next section.
The third example sentence conveys the same meaning as the previous two, but it is much harder for the reader to extract this meaning. Like the second example, the subject of this third example (which is now "the combined mixture") comes rather late in the sentence. Even worse, the subject is separated from the sentence’s main verb (allowed) by a complement ("in the laboratory under normal conditions"). Remember, complements should almost always be placed either before the subject or after the main verb, not between them.
The next section provides specific advice for applying the basic sentence structure to your own writing.
Best Practices for Writing Research in English
Now that you are equipped with an understanding of the basic sentence structure for academic writing, you can take advantage of the specific advice provided in this section. Each piece of advice is given its own subsection.
Put the Main Verb Close to the Beginning
If you look at the sentence trees in the previous section, you’ll see that each one starts by branching off into two paths at the top. The left branch represents the sentence's main noun phrase (which always contains the subject). The right branch represents the sentence's main verb phrase. This verb branch can sometimes be very long, as it can contain several other types of phrases. Meanwhile, the left branch should be as short as possible.
The head of the verb phrase (i.e., the main verb) is the most important word of any sentence. Once a reader gets to this verb, they will automatically categorize the words that came before it as the subject (i.e., the thing that the sentence is about). At the same time, they will expect this verb and any words that follow to describe an action performed by (or to) the subject.
The main verb of a sentence gives readers something to connect all other words in the sentence to. As such, when the main verb comes late in a sentence, the reader will probably not remember what the subject is. Therefore, they will likely need to read the sentence multiple times to understand it. This is the case for the sentence below (I have underlined the main verb).
Poorly written: Even in cases where the women involved have intense psychological malaise as a result of the abuse to which they have been subjected by their partners, not all studies reveal a tendency towards the consumption of substances. (Rivero, Bonilla-Algovia, & Vázquez, 2020)
The main verb (reveal) is the thirtieth word in the above sentence, indicating that the introductory phrase is too long. The sentence is much easier to understand when rearranged so that the main verb is closer to the beginning.
Improved: Not all studies reveal a tendency towards the consumption of substances, even in cases where the women involved have intense psychological malaise as a result of the abuse to which they have been subjected by their partners.
Even though this sentence contains the same words as the first example, it is easier to understand. This is because readers have relatively little trouble digesting large amounts of information after the subject and main verb of a sentence have been given.
Explain What Was Done Before Explaining Why
This rule is related to the previous one. When you explain the purpose behind doing something before stating what was done, you often make the reader wait too long to get to the main verb of your sentence. The writer of the example below made such a mistake (again, I have underlined the sentence’s main verb).
Poorly written: To evaluate the effectiveness of therapy in a real-world setting by using observational data in a relatively unbiased way, we developed the method described in the following section.
The first half of the sentence could be a response to the question, “Why did you develop this method?” Meanwhile, the second half of the sentence could be the answer to the question, “What did you do?” This is the reverse of what readers of academic writing want—they prefer when authors answer the what question first and the why question second.
Because of the author's mistake, the subject (we) and main verb (developed) are introduced too late. This example is made much easier to read by rearranging it.
Improved: We developed the method described in the following section to evaluate the effectiveness of therapy in a real-world setting by using observational data in a relatively unbiased way.
While the first example is difficult to read, it is not ungrammatical. However, similar sentences (often starting with to or in order to) often are ungrammatical due to what is known as a dangling modifier.
Dangling modifiers occur when an introductory phrase describes an action but the performer of that action is not named later in the sentence. This is the case in the following example (I have underlined the dangling modifier).
Poorly written: To evaluate the effectiveness of therapy in a real-world setting by using observational data in a relatively unbiased way, the method described in the following section was developed.
The people who did the evaluating (i.e., the researchers) are not mentioned. So, in this case, it is not only helpful to revise this sentence—it is necessary to avoid a grammatical error.
Improved: The method described in the following section was developed to evaluate the effectiveness of therapy in a real-world setting by using observational data in a relatively unbiased way.
Concrete Nouns Make Better Subjects than Abstract Nouns
Simply put, a concrete noun names something that can be identified using the five senses. If you cannot imagine what a noun looks, sounds, smells, tastes, or feels like when you read it, then it is probably an abstract noun.
Consider the following sentence from an article about business operations (the subject is underlined).
Poorly written: Creativity can generate significant advantages.
What does creativity look like? What does it sound like? Taste like? There are no answers to these questions. Therefore, creativity is an abstract noun, and we can probably think of a better word to use as the subject.
Using abstract nouns, especially as the subjects of sentences, causes two notable issues. First, abstract nouns do not denote anything or anyone that the reader can picture in their mind as they read. As a result, the rest of the sentence will almost always be difficult to understand. Even though the example sentence above is only five words long, it is not easy to tell exactly what the author is trying to say because creativity means different things to different people.
Second, abstract nouns enable the writer to be vague. In the example above, we do not know whose creativity is being talked about because it is presented merely as a general idea.
Below, the sentence has been revised so that the subject is a concrete noun.
Improved: Managers can generate significant advantages by fostering creativity among employees.
Despite being longer than the original, the revised sentence is easier to understand because it is relatively easy for a reader to imagine a manager encouraging their employees to be creative. This might even be something that readers have experienced themselves.
Avoid Dummy Subjects
In English, the subject of a sentence must come before the main verb (except in special cases that are beyond the scope of this article). Therefore, the words it and there are sometimes used as "empty" subjects to prevent this rule from being broken. Such subjects are referred to by linguists as dummy subjects. These words have no meaning—their purpose is strictly functional.
Because dummy subjects are meaningless, their use should be avoided whenever a good alternative is available elsewhere in the sentence. To explain what I mean, I will improve the sentence below, which contains a dummy subject (underlined).
Poorly written: It is because of the interconnectedness between social, psychological, and biological factors that the goal of medicine cannot simply be to correct deviations from illness. (Lopez, 2019)
This sentence contains a noun that would make a fine subject (i.e., goal). If I re-order the sentence’s two main phrases, I can make goal the subject of this sentence, which is a better alternative to the dummy subject.
Improved: The goal of medicine cannot simply be to correct deviations from illness because of the interconnectedness between social, psychological, and biological factors.
In some cases, the dummy subject does not need to be replaced. It can simply be removed instead.
Poorly written: It is for this reason that the modern concepts of informed consent have been developed. (Tribble & Julliard, 2019)
Improved: For this reason, the modern concepts of informed consent have been developed.
Sometimes, using a dummy subject is the best option. This tends to be the case when using a concrete noun would force you to use a very weak verb, such as exist, as the main verb. In such instances, forcing yourself to avoid a dummy subject sounds unnatural.
Poorly written: Over 600 species of tropical timbers exist in the world.
Well-written: There are over 600 species of tropical timbers in the world. (Pijut et al., 2012)
Avoid Noun Strings
A noun string occurs when several nouns are written consecutively. Noun strings are difficult to understand, especially for readers who are not experts on the subject being discussed.
The following example contains a noun string (underlined).
Poorly written: Here, we define the key elements of successful business performance improvement strategies.
In many noun strings, you will find at least one word that can be easily converted into a verb. For instance, the above example includes performance, which is close to the verb perform, as well as improvement, which is close to the verb improve. Noun strings can often be fixed by identifying these words and changing at least one of them into a verb. This has been done in the example below.
Improved: Here, we define the key elements of successful strategies for improving business performance.
Write in the Active Voice Whenever Possible
A sentence is written in the active voice when the subject performs the action described by the main verb. Meanwhile, a sentence is written in the passive voice when the action is being done to the subject.
I have included the following examples to illustrate this difference.
Active voice: All participants signed an informed consent form.
In the example above, the main verb is signed, and the participants (which is the subject of the sentence) did the signing. Therefore, this sentence is written in the active voice.
Passive voice: An informed consent form was signed by all participants.
Here, the main verb is the same (signed), but now the subject (an informed consent form) does not tell the reader who did the signing. Instead, it tells the reader what was signed. This sentence, therefore, is written in the passive voice.
For sentences as short as the examples given above, it does not matter whether you use the active or passive voice. However, as a sentence grows, it becomes more important to write in the active voice to ensure that your writing is clear.
Below is an example of a long sentence written in the passive voice.
Poorly written: The inconsistency between the role assigned to the budget and the quest for efficiency has been remedied by the recent introduction of “standard cost per student.” (Modugno & Di Carlo, 2019)
The main verb of this sentence is remedied, but the thing that has remedied the inconsistency (i.e., "the recent introduction of 'standard cost per student'") isn’t named until the end of the sentence. As a result, the reader might need to read this sentence more than once to understand it.
Writing in the active voice, as has been done in the following example, is helpful to the reader.
Improved: The recent introduction of “standard cost per student” has remedied the inconsistency between the role assigned to the budget and the quest for efficiency.
Use One Independent Clause per Sentence
Linguists commonly refer to phrases as “clauses.” When linguists speak of an independent clause, they mean a phrase that can stand alone as its own sentence. In scientific writing, sentences often contain two independent clauses, such as the example below (I have enclosed each independent clause in brackets).
At room temperature, [water molecules are mobile], and [this enables highly dissociated ions to move rapidly]. (Choo et al., 2020)
As you can see, each phrase in brackets could be its own full sentence. However, you must be careful when writing such sentences. The example above is clear only because both independent clauses are short. In most cases, it's best to break up sentences that contain two independent clauses.
Like the previous example, the example below contains two independent clauses (again, I have enclosed each one in brackets). However, unlike the previous example, the following sentence is too long to be understood easily.
Poorly written: Because [defining species rarity within community samples produces dependence between species’ relative abundances and the particular distribution of habitats], [we used independent, large data sets to conduct the first quantitative assessment of rarity for a regional assemblage of North American bee species]. (Harrison et al., 2017)
This passage is much easier to read when each independent clause is given its own sentence.
Improved: Defining species rarity within community samples produces dependence between species’ relative abundances and the particular distribution of habitats. Therefore, we used independent, large data sets to conduct the first quantitative assessment of rarity for a regional assemblage of North American bee species.
Use Verbs Instead of Nouns Whenever Possible
Many English verbs can be transformed into nouns, usually by adding a suffix. Some common examples of words that have both a noun form and a verb form writing are effect (noun) and affect (verb), development and develop, investigation and investigate, and observation and observe. For some words, the noun and verb forms are identical (e.g., model, study).
When you use more verbs and fewer nouns, your writing becomes much easier to read. This is illustrated through the two following examples. The first one contains many nouns (underlined) for such a short sentence. The revised sentence contains only three.
Poorly written: We performed an analysis of the effect that unsaturated lipids might have on SPV assay results. (Visnovitz et al., 2019)
Improved: We analyzed how unsaturated lipids might affect SPV assay results.
The revised sentence has two noteworthy advantages over the original. First, the word count has been reduced—this happened primarily because the main verb phrase was shortened from a four-word phrase (performed an analysis of) to a single verb (analyzed). Second, the verbs in the revised sentence (analyze and affect) are less generic than those used in the original (perform and have).
Trimming Your Sentences to Improve Clarity
If you follow the advice given in the previous section, you will drastically increase the chances that your writing will be clear, even if you haven’t mastered the English language. However, you can make your writing even better if you can identify and delete (or replace) unneeded words. This short section provides some specific advice you can follow to fine-tune your writing.
Most unneeded words present themselves either as redundancies or wordy phrases. These types of words are discussed in the following two subsections.
When two words within the same sentence have a similar meaning, only one of them is needed; the other one is considered a redundancy.
In scientific writing, most redundancies occur when an author uses two words that indicate addition (e.g., and, also, furthermore, moreover) or uncertainty (e.g., could, may, might, perhaps, suggest). The example below contains both kinds of redundancies.
Poorly written: The overall expression level was reduced in polycystic cases, and it could also be that this decrease might be related to the reduced function of these kidneys. (Mateescu et al., 2019).
The sentence is easier to read when the redundancies are removed.
Improved: The overall expression level was reduced in polycystic cases, and this decrease might be related to the reduced function of these kidneys.
Improved: The overall expression level was reduced in polycystic cases. This decrease could also be related to the reduced function of these kidneys.
Note that it doesn’t matter which word is deleted from a redundant pair. Both improved examples are equally acceptable.
There are many redundancies that you should avoid. While there isn’t enough room in this article to discuss them all and give example sentences, I provide the following list of the most common redundant word pairs found in academic writing.
such as A, B, and C, for example
while at the same time
Many of the above examples were taken from or inspired by the following sources: https://web.uvic.ca/~gkblank/wordiness.htmlhttps://grammarist.com/wordiness and https://www.dailywritingtips.com/50-plain-language-substitutions-for-wordy-phrases
The term wordiness describes instances where a string of several words could be shortened to one or two words. In the example below, simply by removing wordy phrases, I have cut a 20-word sentence down to nine words.
Poorly written: In some cases, companies are required to make an additional payment in order to increase the number of users covered.
Improved: Sometimes, companies must pay extra to cover more users.
There are endless possibilities when it comes to wordy phrases. I have listed the most common ones below, along with more concise alternatives that you can use.
Wordy phrase: a considerable amount of
Use instead: much
Wordy phrase: a considerable number of
Use instead: many
Wordy phrase: a number of
Use instead: several / some
Wordy phrase: because of this / for this reason
Use instead: therefore
Wordy phrase: came to the conclusion that
Use instead: concluded that
Wordy phrase: despite the fact that
Use instead: even though
Wordy phrase: due to the fact that
Use instead: because
Wordy phrase: during the period from
Use instead: from
Wordy phrase: has an effect / impact / influence / etc. on
Use instead: affects / impacts / influences / etc.
Wordy phrase: has the ability to
Use instead: can
Wordy phrase: in cases where
Use instead: when / whenever
Wordy phrase: in order to
Use instead: to
Wordy phrase: in the majority of cases
Use instead: usually
Wordy phrase: is able to / is capable of
Use instead: can
Wordy phrase: it could be that
Use instead: perhaps
Wordy phrase: it is interesting /surprising / etc. that
Use instead: interestingly / surprisingly / etc.
Wordy phrase: it should be noted that
Use instead: [Simply delete this phrase.]
Wordy phrase: on the basis of
Use instead: based on
Wordy phrase: plays a role in contributing / increasing / preventing / etc.
Use instead: contributes / increases / prevents / etc.
Wordy phrase: previous research by [Author] suggests
Use instead: [Author] suggests
Wordy phrase: provides an opportunity for
Use instead: allows / enables
Wordy phrase: the majority of
Use instead: most
Wordy phrase: the manner in which
Use instead: how
Wordy phrase: through the use of
Use instead: using
Many of the above examples were taken from or inspired by the following sources: https://web.uvic.ca/~gkblank/wordiness.html, https://grammarist.com/wordiness and https://www.dailywritingtips.com/50-plain-language-substitutions-for-wordy-phrases
I hope you have found the advice in this article useful. I'm always happy to help people improve their English, so please feel free to contact me if you have any comments, questions, or requests for future articles. I'm also available if you need the help of a professional editor to revise your manuscript—click here to hire Magnum Proofreading to help you with your next writing project.