Here is a few suggested additions to your truncated words list for the apostrophes in wrong direction. I also made two other small changes also to suit my perferences, I added the (?i) to ignore the case - this is to catch the instances where the first letter has been capitalised and I prefer to look for punctuation / space combination at the end
Code:
[ ]?‘(?i)(ad|at|appen|ard|ave|bout|bye|cause|cept|cos|cuz|couse|eard|em|er|e|ee|ell|fraid|fore|im|is|isself|gainst|less|mongst|neath|nough|nother|nuff|ome|ow|ope|oney|orse|puter|round|scuse|spect|scaped|sides|specially|tween|taint|til|tis|twas|twere|twould|twill|un)([\p{P}|\s])