As a Mktg exec of 20 yrs, do I learn Mandarin or get a Masters cert in Internet mktg to bolster my resume?

As a Mktg exec of 20 yrs in sectors of software, law, IT recruitment, publishing – to bolster my resume at this point in time, which would be more favorable as the first to add – knowing Mandarin Chinese or getting a Masters Cert in Internet Mktg?

If I learn Mandarin At City University of Hong Kong will I be able to use that Mandarin often in Hong Kong?

I am asking people who live in Hong Kong or take classes there if people on the street, in stores, or restaurants speak Mandarin.I know Cantonese is the official language I am simply asking that if I learn Mandarin in Hong Kong will I be able to use it outside …