What significant linguistic change occurred due to the Norman conquest in 1066?

The significant linguistic change that occurred due to the Norman conquest in 1066 primarily involved the addition of new vocabulary to the English language. This event marked a substantial influence of Norman French on English, as the Norman rulers brought with them their language, which mingled with the Old English spoken by the lower classes. Consequently, many French words related to law, art, literature, religion, and government entered English.

While changes in vowel pronunciation and dialect development did occur over time, they were heavily influenced by a variety of factors, not solely by the Norman conquest. The introduction of Latin had already been established prior to 1066, primarily through the influence of Christianity and education, and it was not a direct result of the Norman rule. The most notable and visible change in the period that directly stemmed from the conquest was the influx of vocabulary, which helped shape Middle English and has continued to impact the language to this day.