I was writing an email, and I started off with
I am writing to inform you of certain errors...
However, is this use outdated or awkward in emails (assuming that I don't know the recipient)? What about formal correspondence (e.g. letters)?
I don't believe it outdated, but very much reserved to:
Some guide on writing style will advise you to:
So if you only want to express the intent in a less formal way, a simple "
It is clearly redundant and circumspect. However, it sounds polite, and some situations do call for social niceties.
If I were to act on the information, I'd prefer the more direct style.
As VonC at least implies, the basic construct is somewhat formal. But I think "I am writing..." is slightly informal by comparison with "I write..." - so for me, it sits uneasily with the more formal "...to inform you..."
Interestingly, Google Books bears this point out. The informal version of "...to inform you..." is "...to let you know..."; it turns out the pairing "I am writing to let you know..." (both informal) is much more common than "I write to let you know..." (mixed formal/informal) by 8,840 to 5,960.
Personally, I think the formula doesn't have much to commend it. What's the point in starting a written communication with I write or I am writing? Obviously you are - in the fullness of time they'll be reading what you wrote, so they know that. And do they really need to be told that you're going to tell them something? Just get on and actually tell them whatever it is you want to say.
Thank you for your interest in this question.
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