Roman Drachm and Tetradrachm Coins versus Denarii

[Lucas H]

I haven't found a general, beginner's explanation concerning the circulation of tetradrachm and drachm under Roman emperors, say through the end of the first century (early empire).  I understand many in the provinces read Greek, but not Latin, so emperors wanted the populace to be able to read the coins, but why not issue denarii with Greek inscriptions? 

How common are these coins?  From hoards found, say in the East, is most of the silver coinage tetradrachms and drachms versus denarii?  If I do a search at a popular coin site, I'd say I find 20 tetradrachm for every drachm issued under a early Roman emperor.  Is that reflective of the actual issues, and if so why? Where their smaller Roman silver coins issued in the provinces (say obols)?  I haven't seen anything like that.

Any information on this topic at a general or beginner's level is greatly appreciated.

[Lucas H]

The question above would include didrachm, a term and coin, I just recently learned about when I saw a Flavian didrachm. 

[Robert_Brenchley]

The drachm was a direct eastern equivalent of the denarius, and did have a Greek inscription.

[Lucas H]

The drachm was a direct eastern equivalent of the denarius, and did have a Greek inscription.

Did the didrachm and tetradrachm have equivalents?  Weren't some denarii minted in the east, or were the only silver coins that approximate size drachms?

[Jay GT4]

The Romans for the most part left the local currency alone.  The eastern denominations were what they were before Rome took power.  It's easier to leave what people know, it was part of pacifying the Provinces.  Usually during times of civil war Romans struck denarii and other denominations in the east, for example Brutus, Cassius and even Mark Antony struck "Roman" coins to pay the army.  Of course this is generally speaking and there are exceptions, which I'm sure someone else will point out.