John Walker born (18-3-1732)

Johnson's dictionary had only sporadic notes on pronunciation of 'difficult' items. Walker produced the first complete pronouncing dictionary of English. A fascinating snapshot of late 18th century upper-class (London) speech, including some of the first indications of r-dropping, and value judgments about disapproved variants.
Also includes "Rules to be observed by the Natives of Scotland, Ireland and London for avoiding their respective peculiarities." The "Natives" of London were of course "my countrymen, the Cockneys".
His notation for vowels involves tiny diacritics directly above the vowel letter, which, upon magnification, turn out to be numerals (1-4), each one indicating a different vowel sound. Not very practical, particularly when trying to read an old copy of the book.
http://www.johnwalkerdictionaries.co.uk/doku.php?id=elocution
http://lawlibrary.wm.edu/wythepedia/library/WalkerCriticalPronouncingDictionary1803.pdf
https://en.wikipedia.org/wiki/John_Walker_(lexicographer)