Not only was Malay the lingua franca of trade in maritime Southeast Asia, but the language also found its way into Javanese literature. In coastal towns of modern Indonesia, due to Silk Roads interactions, contact between people from different regions was very common. Literary evidence from 18th century AD from East Java indicates that in coastal regions, Malay was not just a language occasionally used to communicate with different people through interpreters, but was in fact incorporated into Javanese literary texts for an increasingly bilingual population.
One of the most outstanding examples is the book Sêrat Jayalêngkara, written in East Java in the early 18th century. It is of the pesisir literature category, a word meaning "coast" or "coastal area", and was intended for a Muslim readership. However, despite this it contains elements of a Hindu influence, in particular in the use of the term ‘suksma’ or "soul" usually found in Hindu religious texts. The book contains speeches by two characters who talk in the vernacular Malay (which differs from literary Malay) indicating that the author of the work was bilingual or at least had a significant command of the Malay language. It can also be assumed that those in the coastal regions who were expected to read it would presumably also have had knowledge of the language or were possibly even bilingual themselves.
The reason for the use of Malay in East Java’s coastal regions may simply have been as a tool to facilitate trade with those whose first language was the vernacular Banjar Malay. However, there is evidence to suggest that the function of Malay in coastal Eastern Java extended beyond the simple necessity of communicating with merchants and had in fact found its way into literary expressions as a means of communicating spiritual and aesthetic needs particularly within literature. For example, the Malay text inserted into the Jayalêngkara indicates a specific speech "register" (i.e. speech allocated for a specific social situation) of vernacular Malay. This provides further evidence to the claim that the intended readers of this text were fully bilingual and would have understood and been aware of, and possibly even used this speech register in their day-to-day lives.
Additionally, at the same time in the reverse direction there was the use of Javanese words or phrases in Malay literature. Predominantly in this literature, words borrowed from Javanese vocabulary were used in Malay stories set in Java, and in stories where exchanges between Javanese people were taking place.
The nuanced role the Malay vernacular language played in coastal Java reveals the extent and importance of Silk Roads interactions in the development of not only unique literary forms made for a bilingual audience, but more broadly indicates the importance the Silk Roads played in developing modes and means of communicating across diverse populations at the centres of trade and exchange.