It appears that servants who could read and write had a higher value, and might be known for literate persons for speaking with a certain [perhaps haughty] tone.
September 22, 1763
The Pennsylvania Gazette
RUN away from the Subscriber, living in Oxford Township, Chester County, an Irish Servant, named Thomas Cane, late from Ireland;
the Fellow can read and write, about 5 Feet high, of a fair Complexion, short fair Hair, and speaks with a Tone:
Had on, when he went away, a Thickset Coat and Jacket, of a dark Colour, the Coat has remarkable long Skirts, Calf skin Breeches, much dirtied, Worsted Stockings, brown and white; he had also a Pair of short Petticoat Trowsers, with a Seam round each Thigh, half worn Shoes, large Copper Buckles, a Felt Hat, half worn.
Said Fellow came in a Dublin Vessel last May. All Masters of Vessels are forbid to carry him off. Whoever takes up and secures said Servant, so as his Master may have him again, shall have Five Pounds Reward, paid by DAVID KENNEDY, jun[ior].