Celtic Football Club, the Glasgow-based soccer team founded in 1887, is pronounced with a soft "S" sound—"Seltic"—a distinction rooted in linguistic history. When the club played its first match in 1888, the English pronunciation of the word "Celtic" was commonly rendered with an initial "S" sound, reflecting the influence of French, where a "c" before an "e" is typically softened.

The word "Celtic" entered English via French, and during the 18th and 19th centuries, this pronunciation was prevalent in everyday usage. However, over time, historians and linguists began to reconsider the term’s origins. Classical sources such as the Greek term "Keltoi" and the Latin "Celtae" suggested a hard "K" sound at the beginning of the word. As scholarly interest in the ancient Celtic peoples, languages, and cultures intensified, academics increasingly adopted the hard "K" pronunciation, leading to the standard "Keltic" sound in most historical and cultural contexts today.

Despite this broader linguistic shift, the football club in Glasgow retained its original soft "S" pronunciation. Proper names often resist changes in pronunciation even as general language trends evolve, and Celtic Football Club remains an example of this phenomenon. Thus, while references to the ancient peoples and cultural heritage usually employ the "Keltic" pronunciation, the club’s name continues to be pronounced "Seltic."

This divergence highlights how language and history can intersect differently across various contexts, with certain traditional pronunciations persisting in institutions and place names despite changes in academic conventions.