Is Sanskrit regarded as sacred?
Yes, Sanskrit is considered as the divine language. The sages in the ancient time realized the Vedas in the form of sound patterns. Those sound patterns expressed in language form came to be known as Sanskrit after much refinement and addition of meaning to the patterns through the use of syntax and grammar.
So Sankrit language, the way it is, creates unique pattern and sound vibrations when used, especially in the chanting of certain mantras. It is also believed that Sanskrit is the language of communication among the gods. So most hymns and mantras for gods are written in Sanskrit language.
Is sanskrit special in some way?
Yes, it is the oldest living language till today. It is the source of many other languages like Pali, Prakruti, etc. Also many other languages used in the north Indian states came into formation from the gradual corruption of Sanskrit.
Sanskrit has also close relationship with other European languages. For example, English "mother" is a cognate of Sanskrit "mātár'; likewise, father-pitár, brother-bhrā́tar, sister-svásar, daughter-duhitár, etc.
This page lists many other specialties of the language.