A specialized subject to be sure, but if you’re interested in sources for Scots pronunciation in the eighteenth century you’ll definitely want to read Charles Jones’s “Sources for Scots pronunciation in the Eighteenth Century“—and even if the reconstruction of historical pronunciation isn’t your thing, you might be interested in the copious quotes from schoolbooks of the period:
Leonora was a little girl of quick parts and vivacity. At only six years old, she could both work and handle her scissars [sic] with much dexterity, and her mamma’s pincushions and huswifes were all of her making. She could read, with ease and readiness, any book that was put into her hand; She could also write very prettily, and she never put large letters in the middle of a word, nor scrawled all awry, from corner to corner of her paper. Neither were her strokes so sprawling, that five or six words would fill a whole sheet from the top to the bottom; as I have known to be the case with some other little girls of the same age.
And here’s a recommendation to cure nonstandard pronunciation at the earliest possible age:
It ought to be, indispensably, the care of every Teacher of English, not to suffer children to pronounce according to the dialect of that place of the country where they were born or reside, if it happens to be vicious. For, if they are suffered to proceed in it, and be habituated to an uncouth pronunciation in their youth, it will most likely remain with them all their days. And those gentlemen who are so captivated with the prejudice of inveterate custom, as not to teach to read by the powers of the sounds, ought in duty, at least, to make their scholars masters of the various formation of the vowels and diphthongs, and of the natural sounds, or simple contacts of the consonants both single and double, whereby they may form the various configurations of the parts of the mouth, and properly apply the several organs of speech in order to speak with ease and propriety. And as children do not commence scholars so soon as their capacities admit, or often on account of their speaking but badly, if they were taught the mute sounds or simple contacts of the consonants, it would immediately enable them to pronounce with a peculiar distinctness. I had a child lately under my care, of about nine years of age, whose speech from the beginning was unintelligible to all, but those who were acquainted with her manner of expression. After I had taught her the sounds of the consonants, and the proper motions that were formed by these contacts both in her own, and by looking at my mouth, I brought her by a few lessons to pronounce any word whatsoever. And by a short practice, she spoke with perfect elocution. This method effectually cuts stammering or hesitation in speech, either in young or old; especially if a grown person be taught to speak for some time with great deliberation. [Buchanan, Linguae Britannicae (1757), p. xii nt.]