Florentine (fiorentino), spoken by inhabitants of Florence and its environs, is a Tuscan dialect and an immediate parent language to modern Italian.
Its vocabulary and pronunciation are largely identical to standard Italian, though the hard c [k] between two vowels (as in ducato) is pronounced as a fricative [h], similar to an English h. This gives Florentines a highly recognizable accent (the so-called gorgia toscana). Other traits include using a form of the subjunctive mood last commonly used in medieval times, a frequent usage in everyday speech of the modern subjunctive, and a shortened pronunciation of the definite article, [i] instead of "il".
Dante, Petrarch, and Boccaccio pioneered the use of the vernacular instead of the Latin used for most literary works at the time.
Italian is the official language of Florence. English is also widely spoken in the tourist areas. For those venturing off the beaten track, it's always good to learn a few Italian phrases. Simple greetings can go a long way. If memorizing key phrases such as 'Ciao. Come stai oggi?' and 'Dove si trova il tuo albergo?' isn't your strong point, try using a pocket size phrase book or carrying a list of pre-written phrases in English and Italian. If worse comes to worse, remain calm, smile and go with the flow because it's all part of the travelling experience.