It includes lot of emotions, feelings, foot work, body postures and a Bharatnatyam dancer needs to express extremely well. This is how the dancer speaks to the audience.
Bharatnatyam is the demonstration of the ancient form of celebration through material body. The audiences can enjoy different abhinayas which is nothing but the physical expression of the dancer. Abhinaya is a must and should be done well in order for the audience to understand what the dancer is trying to say.
Abhinaya is divided into four categories
1) Angikabhinaya: Expressing the meaning of lyrics through body parts like head, hands, legs etc.
2) Vachikabhinaya: Expressing a story via dance drama.
3) Aharyabhinaya: Imitating the dress, jewellery and make-up in the dance.
4) Satvikabhinaya: Showing the devotional moods.
Lord Shiva is the lord of dance and HE is said to be the epithet of all the four kinds of abhinaya.