Ancient Greek was spoken everywhere in Greece but in different dialects from place to place. A common language was developed later between 300BC and 300AD. Modern Greek came later after the Byzantine era.

Greek language is very old and has a long history. It is also considered to be very difficult to learn. But today all visitors can manage very well in Crete, as nearly everybody speaks English and German.

However the locals will be happy if you approach them with a few Greek expressions:

Good morning / Good day : kalimera
Good evening : kalispera
Good night : kalinichta
Hello : yiassas
Yes : ne
No : ochi
Bank : trapeza
Thank you : efcharisto
Please / welcome : parakalo
Water : nero
Wine : krasi
Where is : pou ine

And this might help you read the signs on the road, as some of them are only written in Greek letters:

A α: alfa                        
B β: vita                        
Γ γ: ghamma                
Δ δ: delta                      
E ε: epsilon                    
Z z: zita 
H η: ita 
Θ θ: thita
I ι: yiota  
K κ: kappa
Λ λ: lamda
Μ μ: mi 
N ν: ni
Ξ ξ: ksi  
O o: omikron  
Π π: pi  
Ρ ρ: ro 
Σ σ,ς: sigma
T τ: taf 
Υ υ: ipsilon   
Φ φ: fi   
Χ χ: hii     
Ψ ψ: psii   
Ω ω: omega