The letter J is the tenth letter of the Latin alphabet, used in many languages, and its 'jay' sound helps us read and recognize words.
J/j Facts For Kids
J is the tenth letter of the Latin alphabet, written as uppercase J and lowercase j. You will see it at the start of names and words, and inside words, and its look and sound help readers know which word is meant.
A long time ago J was not separate from I. A writer named Gian Giorgio Trissino helped people see I and J as different letters in the 1500s, and by the 1600s books started to show I and J as separate letters.
In modern English, J most often makes the same sound you hear at the start of jump. That sound is an affricate, where the air is briefly stopped and then released quickly.
In French loanwords J can sound like the s in measure, as in Dijon. In some words from other languages it may sound like the y in hallelujah, and in Spanish jalapeño it can have a breathy sound.
In German, Dutch, Swedish and other Germanic languages, J usually sounds like the English y in yes. Maltese also uses J this way.
In science, uppercase J is the symbol for the joule, a unit of energy. In engineering, lowercase j is used like the math symbol i to mark an imaginary number. In linguistics, the small j in the International Phonetic Alphabet shows the y sound.