First recorded by The Marmalade (1977).
Hit version by Crystal Gayle (US #18/MOR #3/C&W #1 1978).
From the wiki: “The first recorded version of ‘Talking in Your Sleep’ was by the band The Marmalade (‘Reflections of My Life’, ‘Lovin’ Things‘, ‘Ob-La-Di, Ob-La-Da‘), produced by Roger Greenaway (‘I’d Like to Teach the World to Sing‘), released as single in 1977 but without any chart success. It was subsequently recorded in late 1977 by Country music artist Crystal Gayle and released in January 1978 as the first single from her album When I Dream. Gayle’s version became a hit on both the US Country and Pop charts in 1978, reaching #1 on the US Country chart and peaking at #18 Billboard Hot 100 and #3 on the Billboard Adult Contemporary chart.”
Crystal Gayle, “Talking in Your Sleep” (1978):