The difference between formal and informal English is not a difference between correct and incorrect, but a difference of what is known as register. A register is a variety of language related to a particular subject matter or area of activity, a set of words and expressions as well as syntactical features that may be said to characterise that specific area of language.
There are many registers: technical, academic, mathematical, scientific, etc. Very broadly speaking, we can also speak of a “formal” and “informal” register in English. In writing academic reports and the like, it would be normal to draw most of the vocabulary and expressions from the formal register, and few, if any, from the informal.
This entails avoiding colloquial (everyday) or slang expressions in your writing assignments. The question of register is far more complicated than indicated here; for example, there are many degrees of formality and informality. However, below are listed a few examples which may be of practical assistance.
Formal language, even when spoken, is often associated with the conventions expected of written standard English.
Formal English follow rules of grammar very strictly. Sentences tend to be longer and more complex. The vocabulary tends to be elevated, using big words and avoiding colloquial or slang vocabulary. It avoids split infinitives and prepositions at the end of sentences.
Formal language uses a Latin vocabulary and rhetorical devices to create literary-like effects.
Informal language is characterized by a simpler grammatical structure (i.e. loosely-connected sentences and phrases), and personal evaluation. Informal language may make use of slang and colloquialisms, employing the conventions of spoken language. However, it is too casual and loose to be acceptable for academic writing.
They did an experiment
Then the Drive Manager goes through some steps to install the programme
One after the other
They found out what the important things were
You can find out all about the survey on page 7
We think you should discuss the research findings at the next departmental meeting
Doctors have come up with a new method of….
Safety officers are looking into the problem
The cost of cleaning services has gone up 25% over the last three years
We do not think it is a good idea to do anything at the moment
Many thanks to the staff at “Computers R Us” for their help on the technical side
You need to get the patient’s help when doing these hearing tests
There were no big differences between the three different groups we tested
A lot of
This seemed to fix the problem
This shows that …
Numbers are going up
They put the plan into action
This let them keep the same temperature during the whole experiment
These results are because of factors like weight, age …
The experiment was carried out / performed
The Drive Manager then performs / executes a series of functions / operations in order to install the programme
At regular intervals
They determined / discovered / established / identified the important properties / characteristics / issues
Details of the survey are to be found on page 7
It is recommended that the research findings are discussed at the next departmental meeting
Doctors have created / established a new method of….
Safety officers are investigating the problem
The cost of cleaning services has risen by 25% over the last three years
It is suggested that no action should be taken at this stage
Thanks are extended to the staff at “Computers R Us” for their technical support
(Slightly less formal: We would like to thank ….)
When conducting these audiological tests, the active participation of the patient being tested is required.
No significant differences emerged between the three different groups tested
Many / much / a great deal of
This appeared to rectify the problem
Numbers are increasing
The plan was implemented / carried out
This allowed / permitted / resulted in / ensured a constant temperature throughout the experiment / for the entire experiment
These results are dependent on factors such as weight, age …