Going a Little Deeper
For readers comfortable with the basics, ready for more nuance and technique.
The Four Levels of Speech — Parā, Paśyantī, Madhyamā, Vaikharī
How the Ṛgveda, the Pāṇinīya Śikṣā, Bhartṛhari's Vākyapadīya and the Śaiva–Śākta tradition describe the four stages of Vāk — from unmanifest Parā to spoken Vaikharī — and why it matters for mantra and Jyotiṣa.
Understanding the Navāṃśa Chart
An introduction to the D9 chart — why it matters as much as, sometimes more than, the Rāśi chart itself.