Why is English spelling such a tangle? It all started when Latin-speaking missionaries arrived in Britain in the 6th century without enough letters in their alphabet. They had 23. (They didn’t have “j”, “u” or “w”.) Yet the Germanic Anglo-Saxon languages had at least 37 phonemes, or distinctive sounds. The Romans didn’t have a letter, for example, for the Anglo-Saxon sound we spell “th”. The problem continues. Most English-speakers today have, depending on their accents, 40 phonemes, which we have to render using 26 letters. So, we use stratagems such as doubling vowels to elongate them, as in “feet” and “fool”.
With the Norman invasion in 1066, spelling became more complicated still; French and Latin words rushed into the language. As the centuries went by, scribes found ways of reflecting the sounds people used with the letters that they had. They lengthened vowels by adding a final “e”, so that we could tell “hope” from “hop”.
From the late 1300s, scribes used the letter combination “gh” in words such as “night”, to represent the back-of-the-mouth noise people then used. Why did it remain even after the sound died out? Because by the end of the 15th century, William Caxton had introduced printing to England, and the printers decided to keep it.
It is often thought that printing standardised English spelling but much variation remained. While Caxton would usually write “fynysshed”, Crystal also found “finisshed”, “fynisshed”, “fyn-ysshid” and “fynysshyd”. “Musik” sometimes appeared as “musycque” and “them” as “theym”. –Well-chosen words – FT.com.