Last versus latest

[harry]

Can you say: Thanks for your last letter or do I have to say: Thanks for your latest letter?

[Conchita]

Hello Harry,

In my not even remotely humble opinion,... (just joking!: I recently saw the phrase and liked it )

'Thanks fo your last letter' sounds better.

'Thanks for your latest letter' is a bit of a tongue twister and is unnecessary.

Last letter: the one arrived last
Latest letter: the most recent

In business correspondence, however, you would say:

'Thank you for your letter of (+ date).

[Jamie (K)]

[Nicole]

Maybe you remember Steve Martin's Pure Drivel which contains a piece where this guy always calls his ex-girl friend leaving lots of messages on her answer machine. After the third or so message most of his messages end with this line:

This will be my last letter.
or
This will be the last letter I write to you.

This of course is not true because everyone understands that he will call her until she finally reacts somehow. But it shows the meaning of the word last as opposed to latest.
_________________
Life is for living.