Reckon 
In Appalachian and Southern speech, "reckon" can mean to guess, to think, or to be certain - the meaning depends on tone, context, and inflection.
Pronunciation
[REH-kun]
Meaning & Usage
- Guess (verb)
Elmer:
He ever comin' back?
He ever comin' back?
Estel:
Well. I reckon.
Well. I reckon.- Think (verb)
Elmer:
Reckon he'll be real mad f'he does?
Reckon he'll be real mad f'he does?
Estel:
Aww, hard t'say.
Aww, hard t'say.- Absolutely Certain (verb)
Elmer:
Estel:
You got that right.
You got that right.★ The more serious the tone, the stronger the meaning - "I reckon" can go from casual agreement to a firm declaration. ★
Origin and Etymology
From Middle English "reknen" and Old English "gerecenian," meaning to explain, relate, or account for. The modern sense of "suppose" or "believe" came from British English, carried to the American South by settlers, and remains common in Southern and Appalachian speech.
Usage Notes
In the UK, "reckon" can sound more formal, while in the American South it’s everyday speech. Its meaning depends heavily on inflection: a slow, drawn-out "I reckon" often means uncertainty, while a quick, firm one signals certainty.