What is the difference between dialogue and dialog?

I am American, and I always thought the difference between dialogue and dialog was one of meaning, the way Merriam-Webster has them listed:

2 entries found:

• dialogue (noun)
• dialog box (noun)

According to Merriam-Webster, dialogue means conversation, and dialog box means a window on a computer screen.

This is how I use/spell them.

However, at least some people see them as differences between British English and American English.

So my questions, I guess, are:

• First of all, is my understanding, and Merriam-Webster's definition, correct?
• Is dialog used with any frequency by Americans to mean conversation?
• Is dialog not used in British English for the window on a computer screen?
• Is there any other difference I'm not aware of, or perhaps a better explanation for the two versions?

Solution 1:

The only real justification for seeing dialog as "American" is that there are many words where US spelling seems more "logical" than British - largely thanks to Webster, though so far as I know he never addressed this particular issue.

Paraphrasing grammarist.com's entry on another such word: all early editions of Noah Webster’s dictionary list catalogue, but by the 1890s catalog was commonplace in AmE texts (Webster often gets credit for changes he played no direct part in).

There aren't many written instances of dialog prior its rapid uptake by software-oriented writers, but here's one from 1910 Transactions and proceedings of the American Philological Association, where one might reasonably suppose the author to be perfectly literate.

I think it's just that on average people involved in technical writing are more inclined to ignore precedent and go for what seems to them the logical spelling. Consequently we see the short form much more often in computer contexts such as dialog box, leading many people to suppose there are in fact two different words involved (or at least, that the word has two different spellings dependent on context).

It seems to me usage is currently in a "transition phase", but most likely the shorter form will continue to encroach further into traditional, non-computer contexts, and will eventually be seen as standard for all contexts (but for most people, particularly Brits, this hasn't happened yet).

Solution 2:

I was surprised to discover that Americans do indeed use the dialogue spelling when talking about a conversation.

Using the American English corpus:

Ngram

I search for "dialog with" here, because that's a word sequence that would only be used in the sense of "conversation with", and won't match "dialog box".

The graph for the British English corpus is very similar in appearance.

Historical data isn't very useful for a new concept like a dialogue box.

What we see for 2000 is:

• Dialog box
  • American: ~0.00240%
  • British : ~0.00045%
• Dialogue box
  • American: negligible
  • British: ~0.000050%

British people do use dialog, but usually it's when they're making concessions to American readers.

For what it's worth, my British spellchecker doesn't recognise dialog at all.