Have you paid any attention to the letters we use to end our words? For example, you won’t find any words ending in U, V, I, or J. Why is that?

Gareth Adamson has the answer on Quora. And yes, it has to do with history. But also with grammar.

From the blog of Nicholas C. Rossis, author of science fiction, the Pearseus epic fantasy series and children's books

Writing makes you healthy. Grammar, not so much.

Ending with a J

‘J’ is the newest letter of the alphabet, only clearly distinguished from ‘i’ starting in 1633. Most words had already fixed their spelling by then. It remains one of the least common letters and is only used in words of foreign origin, although these do include French words which have been in the language a very long time. There are precious few, if any, Anglo-Saxon words with a ‘j’ in them anywhere, let alone at the end. Since French words cannot end in ‘j’, neither can English words borrowed from French.

Ending with a V

‘V’ is also a fairly new letter. In Old English, the letter ‘f’ was used for what are now considered two separate sounds, ‘f’ and ‘v’, much as ‘v’ is in Modern German. These were considered to be variants of the same sound, and which you used depended on the stress pattern and the position in the word. At the end of a word, it was always pronounced ‘f’. So you couldn’t get a ‘v’ sound at the end of an Old English word. It could occur at the end of a stem, e.g. steorfan, meaning ‘die’ or ‘starve’. In these cases, the ending has often been lost, but we still have a residual ‘e’, as a vestige of the pronounced ending that was once there.

Ending with a U

Loads of Old English words ended in ‘u’, as it was a common noun and adjective ending. But English lost its endings, including that one, and those that remained were neutralized to ‘e’. With the Great English Vowel Shift, ‘u’ by itself came to represent a fairly neutral, transitional sound, which cannot really occur at the end of a syllable, let alone a word. One notable exception is, of course, ‘you.’

Ending with an I

Another uncommon ending is ‘i’. This is for much the same reasons as with ‘u’. The Great Vowel Shift has made a lone ‘i’ into a passing vowel, which, given English pronunciation style, can only go between two consonants (with the obvious exception of ‘I’).

Up to the 15th century, ‘y’ could always be used instead of ‘i’. It was always used where what might have been considered an ‘i’ sound came at the end of a word, probably for reasons of handwriting style: they thought the flourish of the ‘y’’s tail was a better way to end a word. For the same reason, in lower case Roman numerals, they always wrote a final ‘i’ as a ‘j’, e.g. ‘2’ was written ‘ij’, ‘18’ as ‘xviij’, etc. This has come down to us in a lot of words that still end in ‘y’, with a vowel sound quite similar to an ‘i’, but not quite the same. It is modified to end the word gracefully, and that sound became associated with ‘y’, not ‘i’. It is physically possible to end a word with the standard lone ‘i’ sound, as in Monty Python’s Knights Who Say ‘Ni!’ But it sounds silly, and indeed that is the very reason they chose that sound for the knights:

Now, enough silliness! Back to writing!