Please answer a question about the following article about Estonian language:

During the Perestroika era, The Law on the Status of the Estonian Language was adopted in January 1989. The collapse of the Soviet Union led to the restoration of Republic of Estonia's independence. Estonian went back to being the only state language in Estonia which in practice meant that use of Estonian was promoted while the use of Russian was discouraged.

Following the Soviet collapse what became the only official Estonian Language?
Estonian