When writing a letter or email, you must consider your audience and change your tone accordingly. For example, the language you use to write your boss should be different than the language you use when writing a friend. You'll need to do this in the real world and Cambridge examiners are judging your ability to do it on the exam.

In general, we can say:

• Formal writing should make you sound more professional, more intelligent, and impressive.

• Informal writing should make you sound more casual, friendlier, and laid back.

Read the two examples below and note the difference between the tone and language used:

Formal letter: 

I am writing in regards to the call requesting reviews of favourite restaurants as published in the January edition of your Travel Magazine.  

Informal letter: 

I hope you're doing well. As you know, John's birthday is coming up next month and I thought it'd be fun to throw a surprise party for him. 

There's a few basic guidelines we can follow for a Cambridge exam to achieve the correct tone, without going to extremes. 

When writing informal tasks:

• • • You cannot completely relax and write as if you were text messaging a friend in real life. Your grammar and spelling still must be correct on your exam and you cannot swear or use slang like you might with your friends.

    • Never use abbreviations like luv, bcuz, wanna or gonna.

    • Do not use acronyms like ‘LOL’ or ‘OMG’.

    • Do not include emoticons. 🙂

When writing informal tasks:

• Don't try to use over-the-top, antiquated language or phrases

• Aim to write simple, professional communications instead like you might in a business context

When writing a letter, you also do not need to write the address. 

A good dictionary will tell you if a word or phrases is formal or informal. However, at a certain point, double-checking every single word becomes impractical. 

A quick way to find out if the words you know are formal or informal is by checking out lists online. 

Note: do not learn vocabulary from lists. You need to learn vocabulary in context instead. This is just a quick way to double check the words you already know.