is there any variation in the japanese language?
Yes, Ryukyuan languages and the Okinawan Japanese dialect .
Japan
Ryukyuan languages (Amami, Kunigami, Okinawan, Miyako, Yaeyama, Yonaguni), also part of the Japonic language family, are spoken in the Ryukyu Islands chain. Few children learn these languages, but in recent years local governments have sought to increase awareness of the traditional languages. The Okinawan Japanese dialect is also spoken in the region. 
when was the japanese battleship mutsu built? At the end of World War I. which navy did it serve? Imperial Japanese Navy. when was the navy created? In 1868. are they still active? No it was dissolved after Japan's surrender in World War II. was the navy serving an empire? Yes, the Empire of Japan. was there any particular type of democracy in the empire? It is a constitutional monarchy. when did it become a democracy? After 1889. what name did the state take after becoming a democracy? Japan. where did the name japan get its name from? It is based on Chinese pronunciation. how does its demographic look like? As of 2019, Japan has a population of 126.3 million of which 124.8 million are Japanese nationals.
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Japan [SEP] Languages
More than 99 percent of the population speaks Japanese as their first language. Japanese writing uses kanji (Chinese characters) and two sets of kana (syllabaries based on cursive script and radical of kanji), as well as the Latin alphabet and Arabic numerals. Public and private schools generally require students to take Japanese language classes as well as English language courses. Besides Japanese, the Ryukyuan languages (Amami, Kunigami, Okinawan, Miyako, Yaeyama, Yonaguni), also part of the Japonic language family, are spoken in the Ryukyu Islands chain. Few children learn these languages, but in recent years local governments have sought to increase awareness of the traditional languages.