No other Roman province was granted a larger degree of civil rights—a privileged status that allowed for equality before the law. Cambered roads and aqueducts—two of Rome’s great engineering inventions— linked regions that had previously been separated by geography and distance. This promoted a sense of belonging that was furthered by the cornerstone of national unity: language.
Latin, the lingua franca of the early Roman Empire, came to be used and understood by all the tribes of the Iberian Peninsula, and it became the unifying language of trade and government (much like English is in the world today). As the natives became well-versed in Latin, not only did it enable communication with the Romans, but it enabled them to, for the first time, significantly communicate with each other. The downside was that Latin became the main vehicle for undermining local traditions and promoting assimilation. Once a conqueror’s language is spoken, it is easier for them to impose their culture and traditions. (This technique has been used by subsequent Empires—the Spanish, the French, the Portuguese and the British (English). Language is the final means to Empire.)
The Latin script (the alphabet that has its roots as far back as the Phoenicians) spread throughout most of Europe. It is now the most far-spread and commonly used script in the world.
The Romans went a step further with both language and script by inventing the codex (the book format that is commonly used today), which was spread by the Roman Christians via the Bible. So the next time you crack open a book and smooth your hand over the pages, it's the Romans you should thank.