Skip to main content

Overcoming language barriers

Quick links

Concise writing

  • Clear
  • Concise
  • Accurate

When writing your manuscript, be as brief as possible without omitting essential details.

Keep it simple! Simple language is usually clearer; it is more precise and concise than complex language. Though you will often be describing something that is sophisticated, using unnecessarily complicated language will confuse the reader and weaken your message.

  • Ways to keep your manuscript clear, concise, and precise:
  • Only one idea per sentence
  • Use the active voice, not the passive voice, when possible
  • Delete unnecessary or vague words and replace them with more specific words
  • Avoid circular sentences and redundancies

The Purdue Online Writing Lab is a fantastic writing resource and has many more examples of how to make your writing concise.

Professional language editing services

Back to top

Use a professional language editing service where editors will improve the English to ensure that your meaning is clear and identify problems that require your review. 

Two such services are provided by our affiliates Nature Research Editing Service and American Journal Experts - BMC authors are entitled to a 10% discount on their first submission to either of these services. Claim 10% off English editing from Nature Research Editing Service or claim 10% off American Journal Experts.

Comparisons (between, among, like, with, than)

Back to top

Comparisons are frequently made in the Results sections of papers. When making a comparison, remember to:

  • Compare "like" with "like"
  • Avoid being vague - be as specific as possible
  • Words such as "reduced," "increased," and "decreased" can only be used to compare something to the way it was before, not to compare two different things. To compare two different things (e.g., groups of patients), use words such as "higher," "shorter," or "more"
  • Use "between" when comparing two things, but "among" for comparisons of more than two things

BAD: The material from the riverbank was compared with the landfill.

GOOD: The material from the riverbank was compared with that from the landfill.

It doesn't make sense to compare material to a landfill. Instead, we need to compare like with like - that is, material from the riverbank with material from the landfill.

GOOD: Expression levels of p53 in smokers were compared with p53 levels in non-smokers.

BETTER: Expression levels of p53 in smokers were compared with those in non-smokers. Here "those" means "expression levels of p53."

It's best not to repeat the same words in a sentence, since it can bore readers.

BAD: Reactions with the new machine were faster.

GOOD: Reactions with the new machine were faster than those with the old machine.

The first sentence makes the reader wonder "Faster than what?"

BAD: In our study, time until eating and inpatient time after surgery were reduced in the L Group compared with the T Group.

GOOD: In our study, time until eating and inpatient time after surgery were shorter in the L Group than in the T Group. "Reduced" cannot be used to compare two different things.

Proper nouns

Back to top

A noun is a word that refers to a person, thing, or idea. A proper noun is the specific name of a person, organization, or location. Proper nouns always have their first letter capitalized.

The first and last names of a person:

Gillian Welch, Steve Jobs, Derk Haank, Hillary Clinton

Names of companies and organizations:

World Wildlife Fund, United Nations, Volkswagen, Springer

Countries and cities:

Australia, India, Germany, New York, London, Beijing

Months of the year, days of the week

January, Monday

Examples of when not to capitalize:
Nouns that refer to more than one thing:

The experiment was performed at two centers

(see tables 3 and 4)

Names of chemicals or generic drugs:

acetaminophen, benzene


Back to top

There are three articles in English: a, an, and the. These are classified as indefinite (a and an) or definite (the).

Indefinite articles refer to something not specifically known to the person you are communicating with. In other words, a and an are used before nouns that introduce something or someone you have not mentioned before.

"I witnessed an eclipse this morning."

"I wrote a laboratory report before lunch."

A and an are also used when talking about your profession. Examples:

"I am an ethicist."

"I am a scientist."

Use a when the noun you are referring to starts with a consonant sound when pronounced. Examples:

"a city", "a factory", "a hotel", "a university"

If the word begins with a vowel sound when pronounced, then use an. Examples:

"an hour", "an umbrella", "an owl", "an igloo".

Use the when you know that the reader or listener knows or can identify what particular person or thing you are discussing. Examples:

"The results were confirmed."

"Did you unlock the door?"

You should also use the when the thing you are discussing has been mentioned previously; e.g.,

"Each vector encoded a protein with a different reporter molecule. The size of the protein was..."

We also use the when talking about geographical features. Examples:

"the Tropic of Capricorn", "the English channel", "the Himalayas".

We also use the preceding certain nouns when it is known that there is only one of something. Examples:

"the sun", "the world", "the Imperial Palace"

Use of 'respectively'

Back to top

'Respectively' is an adverb that is often misused by non-native English speakers. Use 'respectively' only if your sentence would be unclear without it.

For example:
If we wanted to describe these data in the text of a manuscript, it would be written as:

Oxygen, nitrogen and hydrogen detector flows were set at 85, 7, and 4 mL/min, respectively.

This makes it clear that the first gas mentioned goes with the first number, the second gas goes with the second number, etc.

More examples:
: The two values were 143.2 and 21.6, respectively.

GOOD: The two values were 143.2 and 21.6.

BAD: The two tubes were labeled B and S, respectively.

GOOD: The tubes containing blood and saline were labeled B and S, respectively.

Numerals and units

Back to top

Spell out numbers one through nine, except in the case of units of measure or time. For these, and for values of 10 and higher, use Arabic numerals. Always spell out numbers at the beginning of a sentence if the sentence cannot be rearranged to avoid starting with a number.

Fifteen days previously... NOT 15 days previously...

For a mixture of numbers in one sentence, use a consistent number style.

The sample included 34 men with type A blood, 15 with type B, and 3 with type AB.

Use different number styles when putting two numbers next to each other.

Five 50-kg women, NOT 5 50-kg women

The AMA Manual of Style is a good guide to the use of numerals and units.


  • Generally, in the life sciences there should be no space between a numeral and a percent sign: 48%. In the physical sciences, a space is sometimes included: 48 %. Check the instructions to authors or look at some articles in your target journal.
  • Use a space between a numeral and a unit of measurement: 178 mm.


  • Use a zero before a decimal point, e.g., 0.28 mL

Rates, proportions and fractions

  • Use a virgule (/) for proportions, and a colon (:) for ratios:
  • About 1/3 of samples...
  • The ratio was 3:4.5...
  • The rate averaged 40/100,000 people...
  • Spell out fractions that modify nouns:
  • Half the cases showed...
  • A two-thirds majority...
  • When writing a range or series, give the unit after the final item:
  • BAD: 25 mg-30 mg
  • GOOD: 25-30 mg
  • Do not insert a space on either side of an en-dash (-):
  • BAD: The three sites - Taipei, Shanghai, and Bangkok - all experienced severe weather events in the time period studied.
  • GOOD: The three sites-Taipei, Shanghai, and Bangkok-all experienced severe weather events in the time period studied.


Back to top

Should you use UK or US spelling?

American journals usually require US spelling and British journals usually require UK spelling, but many journals accept either form. If the journal's Instructions for Authors do not specify which to use, just remember to be consistent with the spellings throughout your manuscript.

  • Formatting your manuscript


fiber  fibre
center  centre
labeling  labelling
color  colour

Microsoft Word can help you with correct spellings. Simply select all of the text, then go to Tools>Language and choose the kind of English you want to use. Misspelled words should now be underlined in red - if not, be sure to turn on "Check spelling as you type" under Preferences > Spelling and Grammar.


Back to top

The colon ":" and semicolon ";" are two punctuation marks that are often misused.

A colon is used to introduce a list or a clause that explains the clause before the colon.

There are a number of BMC journals that accept manuscripts dealing with biotechnology: Biotechnology for Biofuels, Journal of Nanobiotechnology, BMC Biotechnology and Microbial Cell Factories.

Semicolons are used in two ways:

  • To separate two independent clauses (clauses that could be complete sentences by themselves) if you do not use a connecting word like "and" or "while" between them.
  • To separate items in a list if some items in the list have commas within them. In other words, semicolons are used instead of commas if commas would be confusing.

The volcano erupted unexpectedly; magma flowed toward three major cities at an alarming rate.

These two clauses could be separate sentences: "The volcano erupted unexpectedly. Magma was flowing towards three major cities at an alarming rate." However, the semicolon suggests that there is a relationship between these two sentences. You can usually tell from the context what the actual relationship is.

She works all day as a nurse in a retirement home; in addition, she is studying in the evenings to become a doctor.

Dr. Benaud is a French researcher; however, he lives in Antarctica.

Thousands of mites crossed the barrier from region A to region B every hour; therefore, it was not possible to count all of them.

Our main findings were that uninsured patients are most likely to visit the emergency room for their health care needs; that children, the elderly, and the unemployed are the groups most affected by lack of insurance; and that the uninsured are a heavy burden on hospitals.

Large, Small, High and Low

Back to top

"Large" and "small" are generally used to express variations or changes in size, dimensions, or mass. "High" and "low" are usually used to express levels or numerical values. "Large" and "small" are often mistakenly used where "high" and "low" would be better.

BAD: Large particulate and ozone emissions were measured in Beijing's air on 278 days in 2009.

GOOD: High particulate and ozone emissions were measured in Beijing's air on 278 days in 2009.

BAD: A low amount of the processor's memory is taken by the browser application and graphics rendering.

GOOD: A small amount of the processor's memory is taken by the browser application and graphics rendering.

BAD: A high fluctuation in average storm drain outflow was detected between June 4 and 18.

GOOD: A large fluctuation in average storm drain outflow was detected between June 4 and 18.