Blah is a nonsense word in English. It is generally used to represent unimportant, unnecessary, or repetitive speech.

Everyone understood the teacher, but he just kept talking, ‘blah blah blah.’

The couple in the back of the bus started fighting, ‘blah blah blah.’

Blah can also be used to stand for generic text. I used it earlier this week in class when showing my students how I wanted their papers to be formatted. (First line of a paragraph indented)

     Blah blah blah blah blah blah. Blah blah blah
blah blah blah. Blah blah blah…

I’m fascinated by language so I found it really interesting that Koreans have an equivalent for blah in their language. They say (maw) as in maw maw maw. For a much longer explanation of blah look here.