Blah-blah-blah and Blah blah blah

Blah blah blah and blah-blah-blah are semantically related In some cases you can replace phrase "Blah blah blah" with "Blah-blah-blah", this phrases are similar.

Blah-blah-blah and blah blah blah are semantically related in empty talk topic. You can use "Blah-blah-blah" instead a noun phrase "Blah blah blah".