Nitpick: su is “substitute user” (sometimes switch user), it merely defaults to root.

man su:

    su - run a command with substitute user and group ID

As for fsck I moved from F S C K to progressively bind the S and C in a slide of the tongue, which ends up sounding like F-ceek once I’ve eased in the audience with F-(s)ceek(ay) (parentheses get progressively toned down as I speak faster)

That or just “FS check”.

You're correct, of course. I don't know why I remember it as super user.

Because that's its most common use - to impersonate as a privileged user - so su quite naturally becomes super user

Because sudo really was “superuser do” and is unrelated to the UNIX utility “su” (at least by lineage.)

I tend to pronounce fsck as one syllable, like "fisk" without the 'i'.

I've always said F S check in my head but never said or heard it on conversation. I started my computer journey with msdos so I think chkdsk is to blame for me saying 'check'.

I'm for su-dough - to my ear it evokes the martial art Judo which makes some kind of sense considering what it does.

On the other hand Soo Doo sounds like a pig farmer's wife calling the swine in for their slop. To my ear ;)

I'm a su-dougher, because "pseudo" reminds me I can be someone else.

In my head I pronounce fsck "fuck" because that's normally what I say when I realize I have to use it. Around people? fs check or filesystem check.

I have always “heard” F sick in my head for fsck

Yeah, me also.

I’ve always called it “fusck”.

That’s how I hear it in my head, probably from years of reading it as a stand-in for profanity on Slashdot and the like.

Yup put me down for "fusck" as well. I am probably inventing memories here but I think it is because whenever I saw a system announce it needed to fsck I would say "oh fuck" in my head (sometimes out loud).