How do you pronounce "Celtic" ?

"Celtic pronounced “Keltic” is an outlier in English phonology. Nearly every other English word beginning ce- has a soft-c sound: cedar, ceiling, cell, cement, cent, cereal, certain, cesspit, and so on (cello, with its “ch-” onset, is another anomaly). So it shouldn’t surprise us that “Seltic” was once overwhelmingly the norm. The now-dominant pronunciation “Keltic” is a modern innovation...

According to the Merriam-Webster Dictionary of English Usage, “the closer you get to circles substantively concerned with Celtic lore and languages, the more likely you are to hear \'kel-tik\”—though “Seltic” may be heard “at times from very well-educated speakers.”..

English is a hotchpotch of languages and lexicons, originally Germanic but with strong Scandinavian, French, and Latin influences. This can lead to specious arguments based on supposedly self-evident logic: It must be “Seltic” because phonology; It must be “Keltic” because etymology. But neither phonology nor etymology dictates usage—that’s down to us, and we’re a contrary bunch.

Claims about correctness in language can’t override the facts of usage, and the important fact here is that both pronunciations are standard and correct. Don’t believe me? Scroll up and consult the dictionaries. Critics are entitled to dislike “Seltic” or “Keltic,” but they have no business saying either pronunciation is wrong. Because they’re both right."