Chinese by many academics is described not as one language but a group of languages. Today chinese is usually described as traditional and simplified chinese. As a spoken language many people think about mandarin and cantonese as the two main different dialects. Mandarin is by far with an estimated 1 billion people speaking it as their first language the biggest one. In total an estimated 1.2 billion speak chinese as their first language.
Danish is a north germanic language closely related to norwegian and swedish. Danish is spoken as a first or second language or a minority language in Denmark, Greenland, Faroe Islands and Schleswig-Holstein in Germany. The specific danish identity evolved a lot during the 18th and 19th century. The early form of danish comes like norwegian and swedish from the old Norse language.
English is the worlds most spoken and spread language. The name english comes originally from a west germanic tribe called Anglia. They were one of many tribes that moved to england during the post roman period. The modern english as we know it today developed mainly during the 15th century. In the 17th century the english language spread through out the world during the colonization up until the 20th century when colonization stopped and conquered countries gained back their independence.
French is one of the most spread languages through colonization mainly to the west (Canada) and south (Africa). There are about 76 million native french speakers. Adding to that there are 70-100 million people that speak it as a second language. There are also a wide range of higher estimations on several hundreds of millions more, no verified statistics behind those latter numbers.
German is a central european language spoken by 95 million people as their first language. Another 10-15 million has it as their second language. German is mainly spoken in Germany, Austria and Switzerland. It is also spoken in Luxembourg. Lichtenstein, South Tyrol in Italy and in a german community in Belgium. Previously german was a second choice for many european countries in school before the global spread of english in the modern era.
Italian is an official language of Italy, Switzerland, San marino and the Vatican state. As a first language it has around 70 million speakers. As a second language the number reaches 90 million people in total. It is a minority language in many countries, especially the neighbouring region. Italian traces its roots back to Latin. It is the most similar language to latin used today.
Japanese is an east asian language spoken by close to 130 million people. It is the national language of Japan. Its documented history dates back to the 3rd century. During the 8th century chinese had influence on the old japanese at that time. during the 12 and 17th century loanwords from the european languages started to appear. The main japanese at the time was located around the Kansai region and Edo, the old japanese capital.