English terms with diacritical marks
The Old English Latin alphabet began to replace the Runic alphabet in the 9th century, due to the influence of Celtic Christian missionaries to the Anglo-Saxon kingdoms. The orthography of Old English – which was entirely handwritten in its own time – was not well standardized, though it did not use all the Latin letters, and included several letters not present in the modern alphabet. When reprinted (on a printing press or computer) in modern times, an overdot is occasionally used with two Latin letters to differentiate sounds for the reader:
Middle English
With the discontinuation of the Late West Saxon standard used for the writing of Old English in the period prior to the Norman Conquest, Middle English came to be written in a wide variety of scribal forms, reflecting different regional dialects and orthographic conventions. Later in the Middle English period, however, and particularly with the development of the Chancery Standard in the 15th century, orthography became relatively standardised in a form based on the East Midlands-influenced speech of London. Spelling at the time was mostly quite regular (there was a fairly consistent correspondence between letters and sounds). The irregularity of present-day English orthography is largely due to pronunciation changes that have taken place over the Early Modern English and Modern English eras.