The oboe and the English horn (or Cor Anglais as it is often called) are cousins, meaning they’re from the same family instruments. They’re not directly derived from each other or are operated in a similar enough way to be considered “siblings.” The English horn itself, unlike the oboe, is considered an auxiliary instrument because of this connection. It’s also about one and a half times larger than the oboe, and features a distinct pear shaped bell. The English horn is more known for its mellow tone, which makes it a good instrument to play mournful, melancholic solos.