Why burg, why berg?
Berg vs. Burg
These two words show up abundantly in family and place names across the Germanic languages (German, Swedish, Dutch, English etc.), so it’s really helpful to keep them straight. Which is tricky, because in modern English, the two have come to be pronounced the same. They didn’t start that way, though, and in the other Germanic languages, they are still distinct.
A Berg “bairk” is a mountain, and a Burg “boork” is a defensive medieval castle. In English, we’ve merged the -er- and -ur- into just -r-, but in German the two are still fully distinct.
The long and short of it~