Its proposal caused a national uproar over the weekend: The general secretary of the Social Democratic Party, Yasmin Fahimi, said the motion had chilling historical echoes, given Germany's xenophobic Nazi past, while a German-Turkish community organization called the motion "absurd."
Criticism was not only limited to opposition parties or groups. Peter Tauber, the general secretary of CSU's sister party CDU, tweeted: "I don't think [politicians] should decide whether I speak Latin, Klingon [a fictional language used by Star Trek characters], or Hessian, at home."
The CSU proposal provoked a Twitter storm under the hashtag #YallaCSU, the Arabic version of "Come on, CSU!" One Twitter user commented: "Dear CSU, please ban foreign-language websites in private living rooms, as well. There is an urgent need for action!" Others mocked the typical Bavarian accents, saying: "Making fun of the CSU is awful. Many CSU members have a hard time speaking German, as well."
Even Germany's foreign ministry participated in the debate, and tweeted on Dec. 6: "We continue to speak in diplomatic language."
Foreigners showed concern whether they would be allowed into the country.
Some business owners were less amused and seemed shocked by the plan.
After harsh criticism, CSU backed off its plan on Monday. A new proposal now states that foreigners should be "encouraged" to speak German at home and in public.
While Peter Gauweiler, the deputy chairman of the CSU, said, "everyone should be allowed the language he or she wants to speak at home," CSU general secretary Andreas Scheuer tried to explain his party's original motion: "We would like families to speak the national language in their everyday lives, as well as with their families so that they are able to enunciate themselves." He denied claims that his party was aiming for the establishment of a 'language police,' but he did not specify how it had originally planned to enforce the proposal in family homes.
Despite the ironic reactions of many Twitter users, a substantial number of Germans would be likely to show support for the CSU proposal. This is a consequence of larger anti-immigrant and Islamophobic attitudes.
The biggest community of immigrants in Germany are from Turkey, many of whose families came under an agreement to live in the country as guest workers in the 1960s. Germany is also accommodating an increasing number of refugees.
These immigrants comprise the bulk of the country's 4 million Muslims. Twenty-seven percent of Germans said in a recent study that Muslims were more aggressive than other citizens. About 20 percent claimed Muslims should not voice public demands in Germany, and 42 percent wanted to limit the construction of mosques.
Surveys have shown similar sentiments in other European countries, such as France. In Germany, however, a country with a catastrophic Nazi past, such opinion polls have raised particular attention and caused concern among civil rights groups and liberals alike.
In recent weeks, thousands of people have taken to the streets to protest, with banners that claim they are "patriotic Europeans who are against the Islamization of the western hemisphere," who are involved in a "homeland security" operation. Most of the protests occurred in the east where more than 10,000 people united in Dresden on Monday; Bavaria is located in the south of Germany.
The protesters argue that immigrants are not willing to integrate into German society, for instance by refusing to speak German. About 17 percent of all people of immigrant descent born in the country speak or write flawed German, according to an OECD study.
In an interview with ARD television on Monday evening, German chancellor Angela Merkel tried to find a compromise: "Good German language skills are essential -- but there are many ways to gain such skills... It is highly beneficial if children have the opportunity to grow up bilingually," she said.