The word one has an irregular spelling and cannot be explained using spelling rules or phonograms. It is one of the 2% of words that is a true exception. Many of the oldest and most common words in languages may have irregular spellings. Often this is because a word's pronunciation shifted over time, or it retained the spelling from an earlier spelling system or language.

The way the word one is pronounced has shifted over time. However, we can use words that are related to this word to understand the spelling.

Exploring the morphological relationships between words provides clues to a word's spelling!