What language does your country speak?

[Tajtek]

The national language is Tajtekaal. You can see a sample here. There are several recognised minority languages - Kruunaal and Elatsaal in the North, both of which are related to Tajtekaal, and Sanasaal in the East along the border with the Republic of Sanaz.

[Herzl Land]

There are two official languages of Israel - Hebrew and Arabic. Within Herzl Land the lingua franca is Hebrew, and is spoken fluently by 100% of the population. 85% of the population speak Hebrew natively, 3% speak Arabic, and the remainder are immigrants or the children of immigrants, who, whilst using Hebrew in their daily lives, speak other languages, most commonly Russian, French and English. English is widely spoken by the population as a second language.

[Arcturus Novus]

The official languages of the Arcturan Empire are English and Latin, though there are donzens of less-common regional languages.

[Xedania]

The official language of Xedania is English, with a more intelligent sounding dialect.

[Ecnard]

English with our own dialect.

[Kanaria]

Official languages in Kanaria are:
English (officially Kanarian English)
Turkish
Kurdish
Maori
Spanish
Salian
Darian
Russian
German
Catalan
Vietnamese
Chinese
Japanese

[Kyrokesia]

80% Kyrokesian
15% Cobata
5% Kegran Islander

Corbatans make up the largest minority group, and they come from the Sabian Plains west of Kyrokesia. Kegran Islanders are small minority with native speakers on the southern coast.

[Bongokarkovia]

Official language of Bongokarkovia is Bongokarkovik, a South Slavic language closely related to Serbo-Croatian. Some influence from Arabic is evident, due to the language mingling with Arabic for several centuries before being officially transcribed, but for the most part, it is a Slavic language. Serbo-Croatian is generally considered one of the easiest languages to learn for people whose first language is Bongokarkovik, and Arabic is the most common minority language. English is rarely understood except by the highly-educated. For the highly educated, Russian and English are very common languages to learn. Working-class people tend to pursue Arabic and Serbo-Croatian since they are more commonly spoken inside the country than English or Russian.

[Kostemetsia]

The lingua franca of the Commonwealth is English. Linguistic makeup differs by colony; the majority languages on Yelan are English and Mandarin; on Mescalero, English, Spanish and Russian; on Esther's World, English, Arabic and French; on Suskind, English and the very occasional Hungarian.

[Bakhara]

Bakhara has two official languages: French and Soninke (Songhai)

[Speckiland]

German.

[Straall]

Scandinavian as the primery then English, dutch, german are the large ones, then we have smaller languages.

[Manchukuon]

The languages of the Sino-Japanese Commonwealth:

Official: Chinese, Japanese.
Recognized: Korean, Vietnam, Russian, English.

[Brandenbourg-Anhalt]

The official national language of Brandenbourg-Anhalt is Brandenbourgish, which is also the first language of the approximately 88 % of the population who are "native" Brandenbourgish people.

English however is also recognized as an official administrative language, meaning that all public sector authorities as well as all public service providers (whether public, private or other entities or individuals contracted by public authorities) are legally obligated to provide an English-language version of all important official publicized documents so that they can also be read by foreign residents of Brandenbourg-Anhalt who might be eligible for certain public services.

Also, public sector entities as well as private and other entities hired as public service providers are strongly encouraged to hire employees that are competent in conversational English.

Brandenbourgish as a language is most similar to IRL German and Dutch.

All Brandenbourgish students are taught English as well as French all the way through primary school (age 5/6 to 15/16/17).
In high school (which is voluntary, three years, any time after primary school) all students continue with English as a subject (mandatory) and are offered to also continue with French (voluntary). They can also choose to start learning another additional language - there is a very wide variety of options offered: Latin, Greek, German, Spanish, Italian, Portuguese, Mandarin Chinese, Japanese, Arabic, Russian, Korean, Vietnamese, Hindi, Bengali, Punjabi, Urdu, Turkish, Malay (both the traditional version and the standardized specifically Indonesian version), Tamil, Marathi, Telugu and Thai.

[Pentecosta]

English, though its known by a different name.

[Carena]

English and Spanish

[The Sol Commonwealth]

Many languages are spoken throughout the planets and moons of the Commonwealth but the most commonly spoken ones are English, Chinese, Hindi, Spanish, Thanatic, Martian, Latin and Arabic.

[Rhyfelnydd]

Welsh is most widespread and the official language, and spoken by 91% of the population as a first language. Around 53% are fluent in english as well. The most prominant minor languages include Gaelic, Cornish, German, Polish and French.

[Thermodolia]

The official languages of Thermodolia are English and Šænsôc.

Examples:

English: The National Republic of Thermodolia

Šænsôc: Grœthást Ræńth Thôdthósć

[Darussalam]

High Darussian is the administrative language of the Eternal State. Classical Darussian is used for Imperial ceremonies, while its native speaker is practically zero the language itself survived in the form roughly the exact same as a millenia and five hundred years ago. The Imperial Clan, and by extension the Imperial Court utilized a pidgin version of Classical Darussian known as Qarawandi. The "Darussian" language itself is comprised of thousands of regional dialects and linguistic styles, not all of which are mutually intelligible with one another.

Other than Darussian the Empire also recognized other 21 languages, this includes the native Shan, Warjend and Kalwak, or the imported Arab, Farsi, Urdu, Turkish, Hebrew, Berber, Balochi, Swahili, Turkmen, Uzbek, or Tajik, among many others. The last is the discouraged and suppressed 'barbarian-tongues', despite the Empire's resolute refusal to recognize these languages there are quite substantial, some mother-derived even, speakers of Greek, German, English, Japanese, Chinese, Russian, and other 'Far Eastern' or 'Far Western' speeches.

tl;dr Austro-Hungary had it easy.

[Minroz]

Standard Mandarin, a variety of Mandarin which is based on the Zhongyang dialect and known in Minrozian as Putonghua (普通话; "common speech"), is the official national language of Minroz and is used as a lingua franca in the country between people of different linguistic backgrounds. Despite its wide distribution, the Mandarin language is virtually homogeneous throughout the country. Mandarin is the most geographically widespread language of the Yazhou continent. Same goes for Menggurian (Mongolian) but not as widespread as Mandarin.

Mandarin is the most used language in Iclamia, on the internet, and is one of the six official languages of the AoN.

[Assadistan]

English as primary, then Arabic, Persian, Russian, French, some Chinese and Japanese as well.

[Magonsate]

Magonsate is primarily an English-speaking country.

[Kedri]

Kedri has no de jure official language, but English is the de facto official language, specifically West Country English.

Spanish, Dutch, and Korean are also fairly common.

[Aterria]

Aterrian English (American English + Some British English) and Some Nipponese (West coast provinces only)