Russian is the most geographically widespread language of Eurasia and the most widely spoken of the Slavic languages. Russian belongs to the family of Indo-European languages and is one of three (or, according to some authorities, four) living members of the East Slavic languages, the others being Belarusian and Ukrainian (and possibly Rusyn, often considered a dialect of Ukrainian). Written examples of Old East Slavonic are attested from the 10th century onwards. Today Russian is widely used outside Russia. Over a quarter of the world's scientific literature is published in Russian. It is also applied as a means of coding and storage of universal knowledge — 60–70% of all world information is published in English and Russian languages. Russian also is a necessary accessory of world communications systems (broadcasts, air- and space communication, etc). Due to the status of the Soviet Union as a superpower, Russian had great political importance in the 20th century. Hence, the language is one of the official languages of the United Nations. Russian distinguishes between consonant phonemes with palatal secondary articulation and those without, the so-called soft and hard sounds. This distinction is found between pairs of almost all consonants and is one of the most distinguishing features of the language. Another important aspect is the reduction of unstressed vowels, which is not entirely unlike that of English. Stress in Russian is neither indicated orthographically, nor governed by phonological rules. Russian is the official language of Russia. It is also an official language of Belarus, Kazakhstan, Kyrgyzstan and the de facto official language of unrecognized Transnistria, South Ossetia and Abkhazia. Russian is one of the six official languages of the United Nations. Education in Russian is still a popular choice for both Russian as a second language (RSL) and native speakers in Russia as well as many of the former Soviet republics.

Spanish (español ) or Castilian (castellano) is a Romance language originally from the northern area of Spain. From there, its use gradually spread inside the Kingdom of Castile, where it evolved and eventually became the principal language of the government and trade. It was later taken to Africa, the Americas and Asia Pacific when they were brought under Spanish colonial rule between the 15th and 19th centuries. Today, it is one of the official languages of Spain, most Latin American countries and Equatorial Guinea. In total, 21 nations use Spanish as their primary language. Spanish is also one of six official languages of the United Nations. The language is spoken by between 322 and 400 million people natively, making Spanish the most spoken Romance language and possibly the second most spoken language by number of native speakers. Mexico has the world's largest Spanish-speaking population. Spanish is the second most widely spoken language in the United States and by far the most popular studied foreign language in U.S. schools and universities. Spanish is among the most popular foreign languages for study in the rest of the nations of the Anglosphere in general, where on top of the widespread use of English globally, the large number of additional countries and geographic territory that Spanish allows exploring is an attractive prospect for many people. Due to proximity, linguistic similarities, and trade reasons it is also a very popular second language in France, Italy, Portugal, and particularly the southern states of Brazil. It is estimated that the combined total of native and non-native Spanish speakers is approximately 500 million, likely making it the fourth most spoken language by total number of speakers. Global internet usage statistics for 2007 show Spanish as the third most commonly used language on the internet, after English and Chinese. Spaniards tend to call this language español (Spanish) when contrasting it with languages of other states, such as French and English, but call it castellano (Castilian), that is, the language of the Castile region, when contrasting it with other languages spoken in Spain such as Galician, Basque, and Catalan. This reasoning also holds true for the language's preferred name in some Hispanic American countries. In this manner, the Spanish Constitution of 1978 uses the term castellano to define the official language of the whole Spanish State