The spelling convention
For many centuries in England people spelt words the way they wished and even chose several ways of spelling a word in the same piece of writing. Although there were periods when English spelling was relatively stable and various attempts were made to standardise spelling, it was not really until Samuel Johnson’s dictionary was published in 1755 that spelling patterns became fixed. Dr Johnson wasn’t always consistent in his dictionary and is responsible for some of the curious spelling patterns that cause difficulties for today’s spellers; for example, he included a ‘p’ in ‘receipt’ but not in ‘conceit’ or ‘deceit’. However, this dictionary and its successors did provide a reference so that people could check their spelling. Once spelling became standardised the ability to spell according to convention became important.
Page 12 of Getting to grips with spelling.