Italian Constitutional Court (Corte costituzionale italiana), No. 170/2010, 19 may 2010

The Piedmont region exceeds its competence by recognising the status of a minority language to a language not included in the mandatory category provided for by the state legislator. Manifest constitutional illegitimacy.

Art. 6 Italian Constitution
Law of the Piedmont Region of 7 April 2009, n. 11
 

It is constitutionally illegitimate art. 1 of the law of the Piedmont Region of 7 April 2009, n. 11, limited to the words "the Piedmontese language" for violation of art. 6 of the Constitution, having exceeded its competence, where it has attributed to the "Piedmontese language", not included in the mandatory group of minority languages ​​referred to in art. 2 of that law, a value similar to that recognised for the latter.
While it is true that there is a regulatory power in the matter of protection of linguistic minorities even in Regions with ordinary statute, it is not permissible to attribute to the latter the autonomous and indiscriminate power to identify and protect their own regional "language" or other "own" languages. "minorities, even beyond what is recognised by the state legislature.