It sure looks like Yiddish. Maybe you'll get more responses if you post this messege in the Other Languages forum.
Here's my (long)shot at a couple of sentences:
4th sentence: עיא האסט דוא גאקומס - How did you arrive?
Last sentence: האלטן וואס אונץ דעיר - The old people that we are / us old people?
Welcome to the forum AlGandhi.
As Maayan said, you should go to Yiddish language forum (I think there is one).
Yiddish is written roughly with Hebrew letters, but it is closer to German (Old German).
Here (for example), in the two examples given by Maayan, it would be (I think) :
. 'i hast du gekoms : How did you arrive/get here
. alten vuss unz der (?) : us old people (?)
It is definitely Yiddish, and a fairly elegant hand, at that. I would really need a much higher resolution copy of the text to read and translate, but I can say for sure that Maayan's transcription is incorrect in a significant number of characters, although I think he is correct that the orthography preserves some of the Germanic forms that were weeded out of Yiddish starting in 1900 (but probably lasting individually into the 20's). The second and fourth words of the bottom line (I can't resolve the others cleanly) are "halten" ("to hold" literally or "to assert", or the first or third person plural thereof, these days written without the ayin as "haltn") and "oyf" ("on top of" and many idiomatic uses).
Do the WRF rules permit larger-scale reproductions?
To my knowledge there is no Yiddish section in WRF.
No (right), there isn't (unfortunately) a Yiddish language Forum, though in the Forum for "other languages" (as Maayan mentioned) questions about Yiddish are sometimes asked.
I wonder if the postcard here comes from a book called "Yiddishland" ? http://www.amazon.com/Yiddishland-Gerard-Silvain/dp/1584230185 originally in French ...