The Romans spoke Latin. Latin spread through the empire because it was the language of the rulers. The spread of Latin was also helped by the establishment of colonies (settlements) of Romans and Latins around the empire.
Christianity did not easily spread through the Roman Empire. See the related question, "How did Christianity spread throughout the Roman Empire?"
The Songhai Empire contributed to the spread of Islam and Arabic through trade and contact with Arab merchants, scholars, and traders. As the empire grew in wealth and power, it attracted Muslim scholars and traders who spread their religion and language through interactions with the local population. Additionally, the ruling elite of the Songhai Empire embraced Islam, further promoting its spread among the populace.
The Roman Empire.
The British Empire's global spread led to the expansion of the English language as it was used as a common language in colonies and trade. This resulted in the adoption of new words and phrases from various languages, contributing to the richness and diversity of English vocabulary. Additionally, English became a dominant language in international communication and diplomacy due to the influence of the British Empire.
It became the lingua franca of the Western Empire, and the basis of much of French, Italian and Spanish language development.
The language used by the ancient Romans, which spread throughout their Republic, and later their Empire, was Latin.
It was Chrisitanity
The French language originated in France. It gradually spread through colonization, trade, and cultural influence to other parts of the world, particularly in regions that were once part of the French colonial empire.
The Greek city-states within the Persian Empire revolted. Cities outside the empire intervened and the war spread.
Because the soldiers manning the out posts of the Roman Empire spoke/wrote in Latin as it was the official language of the Roman Empire... ergo if you wanted any association with the Roman Empire you had to know basic latin. Latin really caught on as being the one, uniform language of the whole Roman Empire
Spain spread its language and religion throughout the world (primarily the Americas) through colonization and forcible conversion.
The English language has not really had any trouble managing to survive. Because of the British Empire, the English language was spread across the world.