# A declaration

"This is what Yahweh declares" or "This is a message from Yahweh"

# about Dumah

"about the people of Dumah" or "about the people of Edom"

# One calls to me

Here "me" refers to Isaiah.

# Seir

This is the name of mountains west of Edom. 

# Watchman, what is left of the night? Watchman, what is left of the night?

This is repeated to emphasize that the person asking the question is worried and nervous.