(Reuters) - Russia signaled concern on Wednesday at Estonia's treatment of its large ethnic Russian minority, comparing language policy in the Baltic state with what it said was a call in Ukraine to prevent the use of Russian. Russia has defended its annexation of Ukraine's Crimea peninsula by arguing it has the right to protect Russian-speakers outside its borders, so the reference to linguistic tensions in another former Soviet republic comes at a highly sensitive moment. Russia fully supported the protection of the rights of linguistic minorities, a Moscow diplomat told the United Nations Human Rights Council in Geneva, according...