The second half of 19th century and first half of 20th century are golden age of modern mathematics and science, as many important ideas and theories were proposed and developed within that period of time. I think that German and French were the main languages for the mathematical papers published in that period. After World War II, it is well known that English has gradually become the predominant language for mathematical papers until this date.
I would like to have more statistics such as articles published in major journals in German/French/English/Others between 1850 and 1950 and beyond. Thanks.