One of Shakespeare’s insults is “Thou whoreson zed! Thou unnecessary letter”. He is referring to the letter ‘z’ and this tells us a great deal about how English was spoken in those days.
Today the letter ‘s’ has two sounds, the soft ‘s’ as in “busy” and the hard ‘s’ as in “bus”. Many words, such as “Susie” and “season” contain both. In the middle of the 16th century the letter ‘z’ was very rarely used. Even today it remains the least used letter in the alphabet.
From this we learn that the author and his audience almost always pronounced the letter ‘s’ softly with the ‘z’ sound. So “season” would sound like “zeezon” and “Susy” would be “Zuzie”. When the ‘c’ was followed by either ‘e’ or ‘i’ it too was often pronounced softly.
In some parts of England, especially the south-west, this is still the regional accent and I have fond memories of a bicycle holiday thru Dorset and Somerset. Stopping at some lonely pub to have a refreshing glass of “Zummerzet Zider” and eavesdropping on the local farmers as they chatted just the way they did in Shakespeare’s day.