Title Two: Fundamental Rights, Citizenship and Social Goals
Chapter One: Fundamental Rights
Art. 31 Deprivation of liberty
2 Any person deprived of their liberty has the right to be notified without delay and in a language they can understand of the reasons for their detention and of their rights. They must be given the opportunity to exercise their rights, in particular, the right to have their next-of-kin informed.
Rights during investigation - access to interpreter and translation if questioned in other language
Rights during investigation - informed of belief that crime has been committed
EDIT.