I promised you (when the German bishops visited Rome on March) to express myself in writing about this serious issue in order to forestall such a split in the innermost room of our prayer.
In his letter the Pope also refers to the lack of unity throughout the world in the liturgy. He speaks from the vantage point of one who often prays the liturgical texts in different languages:
Since I often have to pray the liturgical prayers in different languages, I notice that among the various translations it is sometimes hard to find common ground and that the underlying common text often only remains visible from a distance.
The Pope pretty much dismisses as crumbling the former exegetial thesis that these words could be properly translated as "for all". With his impressive skills of biblical interpretation, he demonstrates the biblical roots of the phrase "for many". He gives a programme of catechesis to help the bishops explain to the priests and then to the people why the words "for many" are to be used instead of "for all".
You can read the letter in German here, or in Google translate English here.
You can also read an editorial by Father Federico Lombardi.