I had it ingrained in me to avoid saying "what?" when I didn't hear what someone said, and instead ask "pardon?" to avoid sounding rude.
What if I only need partial clarification of what was said though, and I don't want to force the speaker to completely reiterate what they said just to fill in the part I missed?
For example
How is the ****** coming along?
I could say "pardon?", and force them to completely re-say the sentence again just so I can hear the one part again, or I could say
How is the "what" coming along?
Which most people understand as me asking for them to fill in the "what".
Is this considered rude though? I try to avoid use of "what" in situations like this, but I can't think of another obvious choice.
How is the "pardon" coming along?
Just sounds odd, and is arguably ambiguous, since a "pardon" is an actual thing, unlike "what".
Is "what" acceptable to use here? If not, is there a more accepted alternative?