It is important to try to get the right 'tone' in your letter. This means that, generally speaking, you should aim for a neutral tone, avoiding pompous language on the one hand (as in the first letter at 2.4.1) and informal or colloquial language on the other hand.
A letter may be given the wrong tone by the use of inappropriate vocabulary, idioms, phrasal verbs, and short forms, among other things. Here are a few examples of each, together with a preferred alternative:
you've probably guessed
you probably know
you'll get your money back
the loan will be repaid
to go into property
to invest in property
a couple of hundred quid
two hundred pounds
prices are at rock bottom
prices are very low
prices have gone through the roof
prices have increased rapidly
These are perhaps extreme examples, but the general point is that you should be very wary of
using idiomatic or colloquial language in your letters. Apart from the danger of being misunderstood if your correspondent is a non-native speaker of English, you may also give an impression of over-familiarity.
Your correspondent must be able to understand what you have written. Confusion in correspondence often arises through a lack of thought and care, and there are a number of ways in which it can happen.
Abbreviations can be useful because they are quick to write and easy to read. But both parties need to know what the abbreviations stand for.
The abbreviations c.i.f. and f.o.b., for example, are recognized internationally as meaning cosr, insurance, and freight and free on board. But can you be sure that your correspondent would know that o.n.o. means or nearest offer?
Some international organizations, e.g. NATO, are known in all countries by the same set of initials, but many are not, e.g. EEC (European Economic Community) and UNO (United Nations Organization). National organizations, e.g. CBI (Confederation of British Industry) and TUC (Trades Union
Congress), are even less likely to be known by their initials in other countries. Note, for telephone purposes, that with a few exceptions (NATO is one of them) these abbreviations are not usually pronounced as a word, but as separate letters: /ti: j u: si: / not /Uk/.
If you are not absolutely certain that an abbreviation will be easily recognized, do not use it.
We saw, at 1.1.2, that the use of figures instead of words for dates can create problems.
Numerical expressions can also cause confusion. For example, the decimal point in British and US usage is a full point rather than a comma as used in most continental European countries, so that an English or American person would write 4.255 where a French person would write 4,255 (which to an English person would mean four thousand two hundred and fifty-five).
If there is a possibility of confusion, therefore, write out the expression in both figures and words, e.g. £10,575.90 (ten thousand five hundred and seventy-five pounds, ninety pence).
(Conversely, be wary of the words billion and trillion which mean different things in the UK and USA. For a full treatment of numerical expressions, see Appendix 4 in the Oxford Advanced Learner's Dictionary.)
Special care should be taken when using prepositions. There is a big difference between The price has been increased to £15.00, The price has been increased by £15.00, and The price has been increased from £15.00.
Careless mistakes in a letter can create a bad impression on your reader. Spelling, punctuation, and grammar should all be checked carefully, but there are some other ways in which inaccuracy may spoil your letter.