You're right, there's a lot of voiceovers on many scenes. I'll translate those for you.

Didn't know about the extended SEN scene with the kids but I do remember noticing a lot of additional scenes (such as LUH calling for THX when she comes home) when I first watched the laserdisc version (keep in mind that I've seen this Italian version until 2004 practically)

Did you notice how the black guy is credited as "negro" (="nigger"), lol! However it must be said that in the 70's there was no hint of racism. Nowadays the word negro has become obviously racist but in those days it was a normal word.