Orm was an Anglo-Saxon monk, who probably lived and worked at Bourne Abbey in Lincolnshire in the 12th century. He has a fair claim to be the earliest English phonetician. He wrote a book called The Ormulum, a sample of which you can see above. It was a biblical exegesis in verse, with no great claim to originality or literary worth, but which has one extraordinary quality.
Orm lived at a time, less than 100 years after the Norman invasion of England, when English was at the beginning of the profound changes which would result in the Middle English of Chaucer. He also lived in a place where the influence of Norse on Old English was very strong. Apparently, Orm was disturbed by the inability of his fellows to pronounce English properly and so set about writing his book in such a way as to indicate, to the best of his ability, the pronunciation he thought was correct. This makes the book, together with the later Ancrene Wisse and the wonderfully named Ayenbite of Inwyt, an invaluable resource for scholars documenting the development of the language at this time.
One of the orthographic innovations to be found in Orm’s manuscript is the consistent use of double letters to indicate that the preceding vowel is short. As you can see in the extract, where possible, the letters were stacked one on top of the other. Orm also used various accents, acute, double acute and breve. These too had something to do with vowel length, though at the moment I’m not sure exactly what.
Another thing that Orm did was to distinguish between the different pronunciations of Old English <g>. For a voiced velar plosive [g] he used <g>, for the corresponding fricative [ɣ] he used <ȝʰ> for [j] he wrote <ȝ> and for the close front ending to a diphthong he used <ȝȝ>.
If you’re interested, you can find out more about Orm and his book at The Ormulum Project.