When editing, or simply reading, business documents drafted in English I have noted that certain pairs of words that are pronounced or spelt similarly are frequently confused ? even at times by native English writers! Some of the most common errors are discussed below.

Enquire / Inquire

Traditionally, enquire (enquiry) and inquire (inquiry) are accepted alternative spellings of the same word. Interestingly, usage has evolved differently in America and the UK. In America, inquiry now tends to be used for all purposes, and enquiry (enquire) is very seldom seen. In the UK, however, a distinction has developed between the two spellings: to enquire (enquiry) is used to mean "to ask a question", while an inquiry is an investigation. You might, consequently, enquire what time the inquiry starts.

Despite extensive inquiries there is still no real conclusive proof.
A public inquiry was held into a disputable redevelopment scheme.
The administrators called for a public inquiry.
The company spokesman said "we are carrying out extensive inquiries to establish the reason of the malfunction."
If you wish to know more about our services, please fill in our enquiry form.
General enquiries ? please call xxxxx. Technical enquiries ? please call yyyyy.
I would like to enquire about membership of your organisation.

Affect / Effect

To affect means to change in some way. Depending on the context, it may mean to delay or stop, to hinder, to prevent, to reduce the effectiveness of or to reduce or increase funds. For instance:

Work on the construction has been affected by a bad tropical storm.
?any fact or event that may affect the Lender's financial position.
Share prices may be affected by political outcomes.

The use of effect instead of affect is a common mistake, very likely caused by the similarity in pronunciation.

To effect means to bring about or accomplish. It is more usually used as a noun, in which case effect means the result or consequence of something. Thus:

This contract enters into effect on 1 March.
The parties agree to the following, with effect from 1 March.
? or if any change in law has the effect of increasing the cost of funding the loan.

Alternative(ly) / Alternate(ly)

Alternative(ly) refers to a choice between two possibilities, or something that can be used instead of something else. Such as:

? an alternative solution means that one solution has already been proposed, this is another solution.
We have a choice between two alternatives?
The conference centre is located just off the A16. A road map is provided. Alternatively, you can travel by train?

Alternative is also something of a "vogue word", and is used to describe a different way of living or methods that are different from the accepted norm. For example "alternative energy" refers to energy derived from the sun or the wind; "alternative medicine" refers to the use of homeopathic or traditional remedies or other methods. Other examples include "alternative society", "alternative technology" and "alternative cinema".

Alternate(ly) means to succeed each other by turns (to "take it in turns").

They worked and rested alternately means at times they worked, then they rested, then they worked again, etc.
The monthly meetings will be chaired alternately by Sam and Jane.
? alternately high and low nuisance levels.

Alternately, you can opt for our special luxury package is NOT CORRECT, as presumably the customer is not expected to switch from one product to the other and then back again ? here, alternatively should have been used.