Scottish English developed after the Union of the Crowns in 1603 and the Union of Parliaments in 1701, which made English the official written language, though Scottish English retains some distinguishing features in pronunciation and vocabulary. It has a rhotic accent with post-vocalic /r/ and fewer vowels than Received Pronunciation English, and words are pronounced with monophthongs. Scottish dialects also vary regionally, with Scots spoken in the Lowlands and Gaelic spoken in the Highlands.