You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Switzerland

Context:
Switzerland has four official languages: principally German (63.5% total population share, with foreign residents, in 2013); French (22.5%) in the west; and Italian (8.1%) in the south. The fourth official language, Romansh (0.5%), is a Romance language spoken locally in the southeastern trilingual canton of Graubünden, and is designated by Article 4 of the Federal Constitution as a national language along with German, French, and Italian, and in Article 70 as an official language if the authorities communicate with persons who speak Romansh. However, federal laws and other official acts do not need to be decreed in Romansh.

Question:
What is the least popular official language of Switzerland?

Romansh