This was the claim stated by German Chancellor Angela Merkel recently (and widely reported). The argument is that immigrants are very welcome in Germany (indeed, perhaps needed to help maintain the German economy), but only welcome to stay if they made greater efforts to adopt German culture, including German language.
One concern with this argument is why the situation should be entirely one-sided. We might argue that there is some value in immigrants having some knowledge about their new homeland, including its cultural heritage and language. However, it is the state that has encouraged immigrants to leave their native countries for the benefit of Germany. While it may not be unreasonable to support some measures, it is also not unreasonable to expect -- in return -- that the state, in this case Germany, take measures to better accommodate the new cultures and practices of the immigrants that they have courted. Anything less is unfair at least.
A second concern is whether we can say with any authority that multiculturalism has "utterly failed" in Germany or anywhere else. There is much evidence that multiculturalism has existed for as long as there have been people.
Instead, I suspect this may be posturing ahead of elections with anti-immigration sentiment rising in many countries in Europe and beyond. If it is, then it could be very damaging as immigrants most often bring more benefits than costs. Germany needs a larger workforce and attracting a talented immigration pool must be part of its longterm strategy. However, if immigrants are to provide a major favour and benefit to the state, then the state should offer something in return. One such offer might be greater respect for difference.