Final answer:
Sir Gawain and the Green Knight was written in Middle English, which predates Early Modern English, the language of Shakespeare's works. The text dates back to a time of chivalry and courtly love, distinctly separate from the English used in the 16th and 17th centuries.
Step-by-step explanation:
Sir Gawain and the Green Knight was not originally composed in Modern English; it was written in Middle English, which was used between 1150 to 1500. This places the composition of Sir Gawain and the Green Knight prior to the transition into Early Modern English, which spanned from 1500 to 1690. Notably, the writings of William Shakespeare and Geoffrey Chaucer's 'The Canterbury Tales' are in Early Modern and Middle English respectively.
Understanding the evolution of our language through these periods is crucial for interpreting historical texts accurately. For example, works from the likes of Chaucer and the anonymous poet of Sir Gawain reflect the linguistic and cultural contexts of their times, notable for the development of chivalry and courtly love expressed in vernacular languages.
Furthermore, during the 16th and 17th centuries, which mark the advent of Early Modern English, writers such as Shakespeare adapted existing stories and legends into a rich, poetic language that was designed for theatrical performance. This was the period when the English language began taking on a form that is more recognizable to modern readers and theatergoers.