When incorporating direct quotations into writing, what is the function of parentheses?

The other answer is approved, but it's actually wrong. Brackets and parentheses are NOT the same thing. The actual function of parentheses when incorporating direct quotations into writing is to set apart the citations and signal the reader.

old english did not sound like modern english, which differs widely in phonology and especially in grammar, so taht old english is unintelligible to modern speakers.

the average english was strongly influenced by the anglo-norman as later by the anglo-french. the pronunciation was affected by the norman with the sounds   "/ θ / and / ð / " transcribed as th.

modern english was standarized from the london dialect and extended by the government and administartion as well as by the effects of printing, began to acquire more words from other languages as well to imporve in a more fluent pronunciation.