Unfortunately, that trick's not going to work with every querier!

I also typically respond with "It depends what you mean by speak", but there's no escaping the fact that that sounds waffly to a lot of people and defensive or argumentative to others. A sleazy gay bar is a less than ideal theatre for holding forth on fine distinctions of linguistic skill. (Not that it's stopped me in the past, but I do make some effort not to be a complete social pariah.)