几百年前欧洲各国科学家用什么语言通信？

以前欧洲学者多用拉丁语通信
还有个笑话
当年英国安妮女王去世，她没有子嗣，于是英国人请了汉诺威选帝侯乔治来当国王，是为乔治一世，然而...国王说德语...大臣说英语...最后大家都听不懂...讨论国事用拉丁语。国王嫌麻烦，于是就诞生了首相一职

两者间用的拉丁语

ScienceDirect:
Correspondence between Kepler and Galileo

It should be noted that at this time Galileo was already occupying a chair of mathematics at the distinguished University of Padua, while Kepler had just recently moved to Graz, where, at this time, he was only a teacher of mathematics at a provincial lower school. Obviously Kepler was quite interested in Galileo's reaction to his fledging work as indicated by his own words:
"You must believe me, I'd rather have a critique, even if it is .~harp, of a single understanding man, than the unconsidered approval of the large masses. ,,2 (translation).(这段原文是否拉丁语不清楚，但可以肯定，开普勒懂拉丁语，下文已给出，且读写学术文献时用的也是拉丁语)
Galileo responded at once in Latin on August 4 with a brief appreciative note to be returned by the same emissary, after only a cursory examination of the work and with a request for two additional copies. Galileo also expressed joy in having found in Kepler another supporter of Copernican teaching. He mentioned that he has assembled data in support of Copernicus but is afraid to publish it. 3

Academia:
The use of Latin and the European Republic of Letters: Change and continuity in the seventeenth and eighteenth centuries

Thus, the astronomer Kepler produced his groundbreaking works in theoretical astronomy in Latin.

Johannes Kepler, who was unable to read Italian, reacted to Galileo’s switch from Latin to Italian by arguing that Galileo had commited “a crime against humanity” (crimen laesae humanitatis).13 Humanity here kept a double sense, both the benefits of universal human knowledge and the humanistic code of civility within the Republic of Letters. Kepler was not unique in his fervour against the use of other languages than Latin for scientific texts. But other voices are not hard to find, either. Kepler’s contemporary Francis Bacon argued strongly against the exclusive domain of Latin for theoretical works, and he also put this principle into practice by writing primarily in English. One should not forget, however, that the ideas of Galileo, Descartes, and Bacon soon spread throughout Europe all the same – aided by Latin translations.

https://en.wikipedia.org/wiki/List_of_lingua_francas (类似文章谷歌百度上都有一大堆，我就不赘列了)

Greek and Latin
During the time of the Hellenistic civilization and Roman Empire, the lingua francas were Koine Greek and Latin. During the Middle Ages, the lingua franca was Greek in the parts of Europe, Middle East and Northern Africa where the Byzantine Empire held hegemony, and Latin was primarily used in the rest of Europe. Latin, for a significant portion of the expansion of the Roman Catholic Church, was the universal language of prayer and worship. During the Second Vatican Council, Catholic liturgy changed to local languages, although Latin remains the official language of the Vatican. Latin was used as the language of scholars in Europe until the early 19th century in most subjects. For instance, Christopher Simpson's "Chelys or The Division viol" on how to improvise on the viol (viola da gamba) was published in 1665 in a multilingual edition in Latin and English, to make the material accessible for the wider European music community. Another example is the Danish-Norwegian writer Ludvig Holberg, who published his book "Nicolai Klimii iter subterraneum" in 1741 about an ideal society "Potu" ("Utop" backwards) with equality between the genders and an egalitarian structure, in Latin in Germany to avoid Danish censorship and to reach a greater audience. Newton's Philosophiæ Naturalis Principia Mathematica was published in Latin in 1687: the first English translation did not appear until 1729. In subjects like medicine and theology Latin has been a subject of study until the present day in most European universities, despite declining use in recent years.

http://www.aca-secretariat.be/fileadmin/aca_docs/images/members/Ulrich_Ammon.pdf

During the 19th century a milder version of d‘Alembert‘s fear became true in the form of the three languages French, English, and German which practically every scientist or scholar had to know, though two of them perhaps only passively, in order to keep abreast of the developments in her field.

该文附赠的经典笑话：

“Notre Langue étant répandue par toute l'Europe, nous avons crû qu'il étoit tems de la substituer à la Langue latine, qui depuis la renaissance des Lettres étoit celle de nos Savans. […] L'Angleterre nous a donc imité; l'Allemagne, où le Latin sembloit s'être refugié, commence insensiblement à en perdre l'usage: je ne doute pas qu'elle ne soit bien-tôt suivie par les Suédois, les Danois, & les Russiens. Ainsi, avant la fin du dixhuitieme siecle, un Philosophe qui voudra s'instruire à fond des découvertes de ses prédécesseurs, sera contraint de charger sa mémoire de sept à huit Langues différentes ; & après avoir consumé à les apprendre le tems le plus précieux de sa vie, il mourra avant de commencer à s'instruire.” (“Discours des editeur”, Encyclopédie, Tombe I, 1751: 39f.)


以及几个图例：

图片：NS.png

图片：SS.png