The cantonal government refused to debate the issue again however, instead deciding on a three-step plan in December 2004 to introduce Rumantsch Grischun as the language of schooling, allowing the municipalities to choose when they would make the switch. The decision not to publish any new teaching materials in the regional varieties was not overturned at this point, however, raising the question of what would happen in those municipalities that refused to introduce Rumantsch Grischun at all, since the language of schooling is decided by the municipalities themselves in the Grisons. The teachers of the Engadine in particular were outraged over the decision, but those in the Surmeir were mostly satisfied. Few opinions were heard from the Surselva, which was interpreted either as support or resignation, depending on the viewpoint of the observer. In 2007–2008, 23 so called "pioneer-municipalities" (Lantsch/Lenz, Brienz/Brinzauls, Tiefencastel, Alvaschein, Mon, Stierva, Salouf, Cunter, Riom-Parsonz, Savognin, Tinizong-Rona, Mulegns, Sur, Marmorera, Falera, Laax, Trin, Müstair, Santa Maria Val Müstair, Valchava, Fuldera, Tschierv and Lü) introduced Rumantsch Grischun as the language of instruction in 1st grade, followed by an additional 11 (Ilanz, Schnaus, Flond, Schluein, Pitasch, Riein, Sevgein, Castrisch, Surcuolm, Luven and Duvin) the following year and another 6 (Sagogn, Rueun, Siat, Pigniu, Waltensburg/Vuorz and Andiast) in 2009–2010. However, other municipalities, including the entire Engadine valley and most of the Surselva, continued to use their regional variety. The cantonal government aimed to introduce Rumantsch Grischun as the sole language of instruction in Romansh schools by 2020. In early 2011, however, a group of opponents in the Surselva and the Engadine founded the association Pro Idioms, demanding the overturning of the government decision of 2003 and launching numerous local initiatives to return to the regional varieties as the language of instruction. In April 2011, Riein became the first municipality to vote to return to teaching in Sursilvan, followed by an additional 4 in December, and a further 10 in early 2012, including Val Müstair (returning to Vallader), which had been the first to introduce Rumantsch Grischun. As of September 2013, all those municipalities in the Surselva which had switched to Rumantsch Grischun had decided to return to teaching in Sursilvan, with the exception of Pitasch, which, however, followed later. Supporters of Rumantsch Grischun then announced that they would take the issue to the Federal Supreme Court of Switzerland and announced their intention to launch a cantonal referendum to enshrine Rumantsch