It also says that bus is pronounced ˈbəs, but it's a contraction of French omnibus, that comes from Latin omnibus, which is pronounced ɔmnibus (both in French and Latin), like goose, but with a much shorter oo sound.
Anyway the point was is English language that stole words from other languages and changed their pronunciation, not the other way around.
MW (from your link) says it's pronounced "siŋgyəˈlātə" which is definitely not "tchingulata", no matter what Latin says.