This might be a duplicate, so kindly excuse me if it turns out to be the case.
Do we say "This is his and her height" ? To me it sounds correct, but since we are talking about two separate heights, does my quoted phrase imply that it is both heights added together? (Nobody ever says that, i know)
For example if I say "His and her lexicon" does it mean the accumulated lexicon of Him + Her or is it treated as a separate one for each? Would you ever under any circumstance say "His and her lexicons?"
Perhaps "His and hers lexicon"?
Also, should I tag this under "grammar" or "grammaticality"?