Dropping vowels to shorten names is a terrible practice. Quick, someone give me an idea what $hdnchgdsp means, an Actual Variable from some Bad Code I'm working on today.
It's not just variables names, either. Filenames often need to be shortened, but dropping vowels is not the way to do it. You're left with unpronounceable names that are annoying to type.
The key to effective abbreviation is not removal of letters from the middle of the words, but from the end. Sometimes, it doesn't make sense to shorten a word at all, like "post". If you have a file that is supposed to "post audit transactions", call it "post-aud-trans" or "post-aud-trx", not "pst_adt_trns".