I'd appreciate an assessment of whether this homebrew staff is rated appropriately.
Staff, rare (requires attunement)
A face is carved near the top of the staff, and every time you look away and look back the face’s expression changes subtly. The staff’s previous owner has died and chosen to remain in what had been his focus staff rather than depart for the afterlife.
The soul in the staff can telepathically communicate with you while you hold it. You can’t prevent this telepathic communication. It would be nice if you could, the soul spends most of its time reminiscing about its youth or quietly snoring.
Fortunately, the soul haunting the staff spoke all standard and exotic languages (BR pg 36). The soul can read with your eyes, hear with your ears, and translate for you. You gain the benefits of the Comprehend Languages and Tongues spells while holding the staff. You also have advantage on Arcana and History checks while holding the staff.