The gondoliers generally express themselves in the local dialect. Out of politeness, when they are addressed in Italian, they will often respond in the same language, but in the long run they prefer their own.
They consider vulgar and very bad-mannered any reference made to money and you will never hear them talking loudly about prices because they do not consider themselves at the same level as the market stall-holder or the fair entertainers.
In fact, they use an extremely complicated code inspired by the bright rainbow coloured and in this way their vocabulary appears more polite and gentile.