Bein's I caint have my druthers an' set still, I cal'late I'd better pearten up an' go 'long.
--Tom Sawyer, Detective ix, by Mark Twain, 1896.
'Druthers' is an Americanism that appeared in the mid- to late 1800s. It is a shortening of "I'd rather", although it was rarely used as a verb. This paralleled the dialectical phrase "to have one's rathers", meaning to have one's preferred choice. It may have been an exaggerated and joking form of bad grammar, as it first appeared in writings by Bret Harte (in the form 'drather') and Mark Twain. It is uncertain how common it was in actual spoken language.
Right from its first written appearance, it has been used as a noun, as in "given their druthers...". While it was apparently clear to readers of the day what druthers meant, it remained a dialectical term, stereotypically used by poor folks of little education in the American South.
Notable appearances of 'druthers' include a song in the 1956 musical Li'l Abner, If I Had My Druthers, and a restaurant chain called Druther's, based in Louisville, Kentucky that populated parts of the south during the 1970s and 80s. Most Americans will still recognize the term 'druthers' and be able to tell you what it means, but few still remember the origin, and even fewer still use it.