What is the function of palate?

When elevated for swallowing and sucking, it completely blocks and separates the nasal cavity and nasal portion of the pharynx from the mouth and the oral part of the pharynx. While elevated, the soft palate creates a vacuum in the oral cavity, which keeps food out of the respiratory tract.

What is the importance of hard palate in articulation?

The hard palate holds the roots of the upper teeth, and the alveolar ridge is an essential part of clear articulation. You can feel this ridge just behind the upper front teeth.