What was the official language used across European monarchies in the XII century?

What needs to be pointed out, in addition to the existing answers, that languages in XII-th century did not exist in their modern form - where they are more or less the same for millions of people, living across territories extending for thousands of kilometers and often codified in a standard form via textbooks, grammars, and dictionaries. Rather, in those times languages existed in forms of dialect continua, where French spoken in the South of France was quite distinct (and perhaps incomprehensible) from the French spoken in Paris, although both were clearly different from German varieties. In the same way, a person in the South of France would be more likely to understand a Catalan or Spaniard, who by modern standard speak languages closely related but not mutually comprehensible to French. In some places this state of affairs still exists - like Bosnian-Croatian-Sebian, or Norwegian, Danish and Swedish, or the Swiss and Alsatian dialects of German. In Germany proper dialects have vanished only recently.

This state of affairs had sharply changed with the spread of literacy and the emergence of nation state (which would politically impose a standard language variety, e.g., via schooling or demanding that the official paperwork is done in a certain language.) E.g., Luther's translation of the Bible is often credited with creating modern standard German/

Martin Luther's translation of the Bible in 1522 was an important development towards an early standardization of written German. Luther based his translation largely on the already developed language of the Saxon chancery, which was more widely understood than other dialects and as a Central German dialect, was felt to be "halfway" between the dialects of the north and south. Luther drew principally on Eastern Upper and East Central German dialects and preserved much of the grammatical system of Middle High German.

Thus, the monarch had to communicate either in some highly standardized language that all of them new (such as Latin) or via the help of translators or multilingual individuals, familiar with the necessary language variety. Another standardized language widely spread in Europe was Hebrew - it is not likely that it was actively used by Kings, but it was relevant for merchants and perhaps communicating on economic matters (which were frequently outsources to Jews.) In Spain and nearby areas Arabic was also in common use. I think that ancient Greek had not been yet widespread among educated public in the XII-th century.

According to wikipedia, Anglo-Norman French (the dialect of French spoken by the Norman conquerors) was used for that purpose in England in the 13th century. Before that it was typically Latin, and afterwards English.

(BTW: langues d'oïl basically means a dialect of French where oui is used to mean "yes". Anglo-Norman French was in fact one of those).

For diplomatic communications, Latin was generally used. Remember that the "Romance Languages" (French, Italian, Spanish, Romanian, etc.) were just regional dialects of Latin that slowly drifted into mutual-unintelligability.

Here are the official titles of Catholic European kings in the 13th century.

Lithuania 1261:

Mindowe, Dei gratia rex Littowie

Hungary and Croatia 1270:

Stephanus dei gracia Hungarie, Dalmacie, Croacie, Rame, Seruie, Gallicie, Lodomerie, Cumanie Bulgarieque rex

Denmark and the Wends 1251:

Abel dej gracia Danorum Slauorumque rex dux Jucie

The Franks (France) 1246:

Ludovicus, Dei gratia Francie rex

The Swedes and the Goths 1276:

Magnus dei gracia sweuorum gotorumque rex

Bohemia 1291:

Nos Wencezlaus, dei gratia rex Bohemie, dux Cracouie et Sandomerie, marchioque Morauie

England 1261:

Henricus, dei gracia Rex Anglie Dominus Hibernie et Dux Aquitannie

The Scots 1240:

Alexander dei gracia Rex Scottorum

Sicily Naples 1289:

Karolus secundus, Dei gracia rex Jerusalem Cicilie, ducatus Apulie & principatus Capue princeps Achaye, andegavie provincie et forcalquerii comes

the other Sicily 1282:

Petrus dei gracia Aragonum et Sicilie Rex

Latin Empire of Constantinople 1205:

Balduinus, eadem [Dei] gracia fidelissimus in Christo imperator, a Deo coronatus, Romanorum moderator et semper augustus, Flandrie et Hainoie comes

Jerusalem 1258:

Conradus dei gratia Ierusalem et Sicilie rex, dux Swevie

Antioch 1219:

ego Raymundus Rupini dei gracia princeps Antiochenus, Raymundi principis fili

Cyprus 1252:

Nos Henricus Dei gratia rex Cypri

Norway 1264:

Magnus dei gratia rex Norwagie

Poland 1295:

nos Premislius secundus, Dei gracia rex Polonie et dux Pomoranie

Portugal 1259:

ego Alfonsus dei gratia Rex Portugalie

Aragon, etc. 1231:

nos Jacobus, Dei gracia, rex Aragonum et regni Majoricarum, comes Barchinonensis et dominus Montispessulani

Castile, etc. 1249:

ferdinandus Dei gratia, Rex Castelle et Toleti et Legionis et Gallicie et Seuille et Corduue et Murcie et Jaheni

Navarre 1223:

nos Sancius, Dei gratia rex Nauarre

Emperor 1226:

Fridericus secundus divina favente clementia Romanorum imperator semper augustus, Jerusalem et Sicilie rex

http://eurulers.altervista.org/index.html1

What language are these title from 13th century documents written in? Almos t all are in Latin. They show that many documents in Catholic European countries were written in Latin.