My answer to a question asked in #vedists about war-cries in the Véda: The Mántra-s do mention war-cries or at least war-noises several times (krándas R̥V 2.12.8, 6.25.4, 10.38.1, 10.121.6; ākrandá AV 12.1.41; bhára-hūti R̥V 1.129.2, 5.48.4, 8.63.12). Unfortunately, there is no dialogue I’ve encountered in any Mántra or Brā́hmaṇa that is explicitly indicated to be a war-cry. However, there are some invocations that seem to serve almost as war-cries. Thus the formula recited alongside the beating of war-drums (dundubhí-s, TB 1.3.6.2) before the chariot-race of the vāja-péya:
Índrāya vā́caṁ vadata—Índraṁ vā́jaṁ jāpayata—Índro vā́jam ajayit!
“To Índra raise your voices—make Índra win the prize—Índra hath won the prize!” (TS 1.7.8.3).
Especially the first two could make for good war-cries. Several other formulæ used in the vāja-péya could also serve the rôle, but this seemed the most pertinent in its application. Another pertinent war-cry could be what was spoken by Bharádvāja at the Battle of Ten Kings (JB 3.244):
Ā́ na Índro hávaṁ gamiṣyati. Jeṣyā́ma imáṁ saṁ-grāmám!
“Índra will come to our call. We will win this battle!”
This occurs in a variety of tenses, e.g. ā́ na Índro hávam agamat “Índra is come…” and jáyāma saṁ-grāmám “let us win…”.