It is not accurate to say that the Hungarian language has declined. In fact, Hungarian is still widely spoken and is the official language of Hungary, where it is spoken by approximately 98% of the population. It is also spoken by minorities in neighboring countries, such as Romania, Slovakia, Serbia, and Ukraine.
However, there have been periods in Hungarian history where the language faced challenges and obstacles to its use and development. For example, during the 19th and early 20th centuries, Hungary was part of the Austro-Hungarian Empire, and the use of Hungarian was discouraged in official and administrative contexts in favor of German.
In addition, after World War II and the Soviet occupation of Hungary, there was a push to promote Russian as the dominant language in education and other areas, which led to a decline in the use and status of Hungarian. However, after the collapse of the Soviet Union and the end of Communist rule in Hungary in 1989, there has been a renewed focus on the promotion and protection of the Hungarian language and culture. Today, Hungarian is a thriving and vibrant language that continues to play a vital role in Hungarian society and identity.