Natyashastra
संलापरचितैर्नित्यमुक्तप्रत्युक्तमिष्यते । वज्रार्धेन प्रकर्यास्तु तस्य तालविधिः स्मृतः ॥ ३२७॥
It is always performed through dialogues and counter-dialogues, and its rhythm or time-measure (tāla) is prescribed to be executed in the half measure of the Vajra rhythm.
english translation
saMlAparacitairnityamuktapratyuktamiSyate । vajrArdhena prakaryAstu tasya tAlavidhiH smRtaH ॥ 327॥
hk transliteration by Sanscript