Theory:

     Parai Aattam is a special type of dance in Tamil culture in which the performers beat the parai and dance to its rhythm. This is one of the oldest traditional dances. In olden days, the parai was used for multiple reasons, ranging from warning people about the upcoming war, requesting civilians to leave the battlefield, announcing victory or defeat, stopping a breach of a water body, gathering farmers for farming activities, warning wild animals about human presence, during festivals, weddings, celebrations, worship of nature and so on. Parai Attam plays a prominent part in all the celebrations in Tamil Nadu even today.
 
     Bommalaattam or Puppetry is held in rural areas of Tamil Nadu during festivals and fairs. Skilled puppeteers manipulate the puppets with strings or wires. They stand behind a screen and the puppets are held in front. The puppetry depicts stories mainly from the Puranas, epics and folklore. Even during Indian freedom struggle awareness programmes for the common people were conducted through puppet shows to instill patriotism among the people.

     Therukoothu is usually conducted during village festivals in the months of Aadi and Panguni. Theru koothu is performed on the streets and in open air. In this dance form, make-up and costumes are considered very important. The performance involves storytelling, songs, dance and dialogue rendering. The performances are based on stories from Puranas, Ramayana, Mahabharata, and the local folklore.
 
     Silambaattam is a martial art form, practiced from the days of the Tamil kings. It has metamorphosed into a non-violent form of folk dance, adding stepping styles into the dance to the measure of time. This martial art form also teaches the performer the methods of self-defense.
Explanation:
 
Parai Aattam is another form wherein the group will beat the parai (drum-like native percussion instrument), which sounds different. This is the oldest form of dance. People in ancient days used this art for many reasons like announcing something which the King would have said, victory or defeat in the battlefield, gathering people, or warning wild animals, etc. Even today, this dance form is famous.
 
Bommalaattam means using dolls or puppets. Those who were good at this form used to pull strings from behind the cloth screen and make them perform a dance or drama to tell stories. Even during India's freedom struggle, they used this art form to inculcate patriotism in people.
 
Therukoothu is performed during March and July. Theru means street, and this dance form is performed on the streets in many villages, towns, etc. This assumes in folklores, songs, dances, dialogues etc from Puranas like Ramayana, Mahabharata, etc. The most important part of Therukoothu is costumes and make-up.
 
Silambaattam is a type of martial art. It is used in folk dance form without being violent. This art form helps in defending ourselves.
Reference:
State Council of Educational Research and Training (2018). Term-1 English Standard-9. Folklore (pp. 134-136). Published by the Tamil Nadu Textbook and Educational Services Corporation.