This excellent series was filmed in both Welsh and English. Not all the crew were welsh speaking so they could only film at certain occasions with a full welsh crew.
When Mared is talking to the minister's wife she says the familiar phrase "spare the rod, spoil the child" saying it's from the Bible. The minister's wife responds that it's not but there is a verse in Proverbs that is close to it which the phrase is derived from. Different translations are worded differently but the NIV version is: "Whoever spare the rod hates their children, but the one who loves their children is careful to discipline them." -Proverbs:13:24