The letter "y" in English can represent different sounds, including the /j/ sound. The /j/ sound is known as the "consonant y" sound or the "yod" sound. The evolution of the letter "y" and its association with the /j/ sound can be traced back to its origins in the English language.
In Old English, the letter "g" was often used to represent the /j/ sound. Over time, scribes and writers began to use the letter "y" as an alternative to represent this sound. This usage was influenced by the Old English rune "gyfu," which also had the /j/ sound.
Furthermore, the letter "y" was used to transliterate words from other languages, such as Greek and Latin, which had sounds similar to /j/. These transliterations contributed to the adoption of the /j/ sound for "y" in English.
As English evolved, spelling conventions changed, and the pronunciation of certain sounds shifted. The /j/ sound associated with the letter "y" remained consistent, even though the pronunciation of other letters and letter combinations shifted over time.
It's important to note that the pronunciation of the letter "y" as /j/ is not universal in all languages. In some languages, "y" represents different sounds, such as /i/ or /ai/. The specific pronunciation and usage of "y" can vary depending on the language and its historical development.