Mercury rules 1st and 4th house is in 12th house in Taurus
As a Jyotish astrologer, I would interpret Mercury in the 12th house in Taurus sign as a placement that is likely to bring about a significant focus on spirituality and inner development for the native.
The 12th house in Vedic astrology is traditionally associated with spirituality, enlightenment, and liberation from material attachments. With Mercury, the planet of intellect and communication, placed in this house, the individual is likely to be deeply interested in exploring various spiritual concepts and practices, and may have a natural talent for communicating spiritual ideas to others.
Taurus is an earth sign, and its influence on Mercury in this placement could manifest as a desire for the individual to ground their spiritual beliefs and practices in practical, tangible actions. The native may be drawn to holistic practices that emphasize both physical and mental health, such as yoga or acupuncture.
However, there may be some challenges associated with this placement as well. The 12th house is also associated with isolation, confinement, and hidden enemies, so the individual may struggle with feelings of isolation or mental distress at times. They may also need to be careful about who they trust, as there may be people in their life who are not what they seem.
Overall, with Mercury in the 12th house in Taurus sign, the native is likely to be a spiritually-minded individual who is deeply committed to personal growth and development. They may encounter challenges at times, but ultimately have the potential to achieve significant spiritual enlightenment and insight.