Lyric discussion by ultramegaunknown 

Cover art for Big Long Now lyrics by Nirvana

I heard somewhere that this song is about witnessing a UFO. The bizarre music and confused lyrics seem to perfectly convey a sense of vertigo. Almost like climbing and climbing without actually ascending.

"I am blind/ Speaking a phrase"

That line seems to refer to the possible opening of an extraterrestrial spacecraft and subsequent "blinding" of the writer who witnessed it, due to the lighting inside the ship. Then, the writer can hear some sort of jargon, "Speaking a phrase."

That's just my two cents.

It's such a lumbering, eerie song that I'm inclined to believe that's the case. Regardless of what the lyrics say, it certainly has the right mood...