In the years during and after the Interregnum "plain" speaking came into vogue. Francis Bacon was praised by the Royal Society for his "mathematical plainness" and lucidity of language. It became trendy to write without the complicated floral Elizabethan epithets and overblown exaggeration that had characterized expression in previous centuries. These idiomatic phrases survived this paring down of language intact.
The result was that the language of the Restoration is not far off our own. Samuel Peyps began most of his diary entries with "Up early and off to my office to..." whatever he was going to do with his day and then ended the entry with "And so off to bed." The direct casual wording sounds modern and it is not until the references to coaches, wenches and nasty, nasty food crop up that the diary really shows its age. Well, that and Peyps' fascination with his digestive system and the commemorating the removal of his "stone" (a yearly celebration in honor of his gall stone surgery--more ick).