A few notes for a work in progress.
First observations :
- It may look like we are facing some 8x8 grid-coding (A->H, 1->8)
- There are 2 'one-letter' words : A4 and C3.
- there is a repeating 'two-letters' word : A8C1
- This word is associated each time with a one letter word.
- the last association is in reverse order, followed by a '?'
- there is another interesting word : A4G8G8, whose first letter is the same as the repeating 'two-letters' word, and the 2 following being the same
And a few not-matching avenues :
- provided the underlying sentence is english...
- Since there are not so many choices for one letter words, I guess One of A4 and C3 is 'I'. The other might be 'A', but since it is associated with what looks like a 2-letters verb (A8C1), it may be a subject, thus, I am thinking about "U"...
- So A8C1 might be "IS", "DO" or "AM"... but since it would have to match 2 different one-letter subjects, I'd say it's "DO". The text would thus be something like "I DO.... DO U"?
- Thus, A8G8G8 would not match here, cause I don't see such a matching word here (but for the unlikely "dee")
- also, I don't see any 8x8 pattern so far matching all the letters I A4 D A8 O C1 U C3
- also, since you are mentionning enigma, I guess it's more of a commutating alphabet, but I still don't see the key to understand how it is performed
Here it is... maybe this will help others, but I am still on it anyway