Was Latin widely spoken by European diplomats in the late 19th century?

Question

If a diplomat from Germany were to attempt to speak Latin with foreign diplomats, would it be feasible that the other party would understand his Latin? Would Latin be commonly understood by diplomats of various European countries in the 19th century?

Answer 1

Was Latin widely spoken by European diplomats in the late 19th century?

In the few cases where the language used by diplomats is meantioned and not French it is stated that they used a language that they were proficient in.

I found no signs that Latin was used as a 'backup' language.

From your original question Was Latin widely spoken by European diplomats in the late 19th century? - Worldbuilding Stack Exchange

Suppose that Imperial Germany hates to speak French, so they decide to use Latin to communicate when visiting foreign powers or speaking with the diplomats of another states.

So it would if Bismark takes that decision, would the foreign diplomats understand/know Latin, so that they would be able to communicate with the German ones?

Bismarck was fluent in at least 4 languages, based on the only voice recording made in 1889 for a Thomas Edison representative. The spoken text of the 74 seconds recording was made spontaneously by Bismarck in English, Latin, French and German. The french text spoken was the first line of the Marseillaise.

• For further details: 2012-01-31: So klang Otto von Bismarck: Sensationelle Tonaufnahmen - DER SPIEGEL (in German)

As the Prussian representative in St. Petersburg and Paris one can safely assume he was a fluent french speaker.

There is no hint that Bismarck was antagonistic towards the french language.

It is known that at the 1878 Congress of Berlin, which Bismarck hosted, the language used was french. The exception was the british PM Disraeli who didn't speak it well. This is a sign that each diplomat used the language they were more proficient in (using a translater when required).

This was the only conference that I could find (during the second half of the 19th century), where the topic of which language was used during discussions is meantioned.

Conclusions:

Any attempt by one person in replacing french with latin as the Lingua Franca is a highly unrealistic scenario, since it is known that diplomats decided for themselfs which language they used.

It is highly unlikely that Bismarck, known as a very pragmatic person, would have attempted such a replacement since it would have brought no benefit to anyone and probably would not have been adhered by anyone (thus serving no pratical purpose).

Even though your original question is tagged alternate-worlds (For questions about worlds other than Earth that are significantly different), it is a unrealistic scenario (both about the person and how diplomats interact with each other).

How diplomats interact with each other, as far as language usage is concerned, is probably true today as it was then.

Answer 2

French was the "Lingua Franca" for diplomats in Europe from mid 16th century to First World War, when English replaced French. French was used by diplomats in Spain, Italy, Germany, etc also in Sweden and Russia.

French replaced Italian. Italian was the main cultural and also diplomatic language in Europe since the 1400'. This is, since the Renaissance.

Latin was an academic language well into the 19th century, but latin was not used primarily by diplomats, altought Latin is occasionally found in diplomatic correspondence.