A battle speech is a specific literary genre, and follows specific patterns. The codifier for this is Thucydides’ Histories; most Greco-Roman and modern battlefield speeches, both literary and historical, follow this same pattern:

1. The opening, focused on the bravery of the men.
2. An acknowledgement of the dangers ahead.
3. The gains from victory and the consequences of defeat.
4. Why the speaker expects the army will win.
5. The conclusion

See, for example, Patton's Speech to the Third Army.

Tolkein doesn't have any battle speeches of this sort in his work. Theodén's poem, and much of Rohirrim culture, comes from the Anglo-Saxon tradition. You can find poems in this pattern in works like Beowulf, and being specific to the Anglo-Saxon/Rohirrim culture, it would be surprising to find elves speaking this way.

A battle speech is a specific literary genre, and follows specific patterns. The codifier for this is Thucydides’ Histories; most Greco-Roman and modern battlefield speeches, both literary and historical, follow this same pattern:

1. The opening, focused on the bravery of the men.
2. An acknowledgement of the dangers ahead.
3. The gains from victory and the consequences of defeat.
4. Why the speaker expects the army will win.
5. The conclusion

See, for example, Patton's Speech to the Third Army.

Tolkien doesn't have any battle speeches of this sort in his work. Théoden's poem, and much of Rohirrim culture, comes from the Anglo-Saxon tradition. You can find poems in this pattern in works like Beowulf, and being specific to the Anglo-Saxon/Rohirrim culture, it would be surprising to find Elves speaking this way.