Is "deepo" an archaic spelling of "depot"?

In several places in Mark Twain and C.D. Warner's novel The Gilded Age, the word "deepo" is used.

One such occurrence is the following:

Dilworthy will be elected to-day, and by day, after to-morrow night he will be in New York ready to put in his shovel—and you haven’t lived in Washington all this time not to know that the people who walk right by a Senator whose term is up without hardly seeing him will be down at the deepo to say ‘Welcome back and God bless you; Senator, I’m glad to see you, sir!’ when he comes along back re-elected, you know.

Is this an old way of spelling "depot," or what is the story here?

Solution 1:

'Deepo' is not so much an "old way" of spelling 'depot' as a way of spelling it typical of a variety of 19th century Southern humor. That variety of humor featured ersatz phonetic spellings in imitation of dialectical and vernacular pronunciations, or at least spellings intended to evoke a sense of such pronunciations by the fictional speaker.

For example, George William Bagby (aka Mozis Addums) in an 1867 publication, uses it thus:

The Native Virginian (Orange, Virginia), 15 Nov 1867, p 2 (paywalled link).

Other examples, although a bit thin on the ground, appear in similar contexts in the popular press in the years prior to the 1873 publication of The Gilded Age. The contexts make clear that 'depot' is the intended word.

Solution 2:

During Twain's time, there was an interest in simplifying non-phonemic English spellings. Twain was sympathetic to this movement and in fact was a member of the Simplified Spelling Board funded by Andrew Carnegie, although he doubted that gradual reforms would be able to gain widespread acceptance ("Mark Twain on Spelling Reform", The Atlanta Constitution, April 22, 1906).

As the standard spelling of the word "depot" is particularly bad at suggesting the pronunciation, it seems somewhat plausible to me that Twain favored "deepo" at least partly because of the increased phonemicity of the spelling, setting aside the matter of eye-dialect or humorous respelling (although those devices certainly were commonly used in Twain's writing, and it seems plausible that they contributed to the use of "deepo").

Mind, I myself am a Simplified Speller; I belong to that unhappy guild that is patiently and hopefully trying to reform our drunken old alphabet by reducing his whiskey.

– "A Simplified Alphabet", 1899