Before he went to university, MacLean was writing in both English and Gaelic. After writing a Gaelic poem, "A' Chorra-ghritheach" ("The Heron"), in 1932, he decided to write only in Gaelic and burned his earlier poems. MacLean later said, "I was not one who could write poetry if it did not come to me in spite of myself, and if it came, it had to come in Gaelic". However, it is also clear from his correspondence with MacDiarmid that his choice was also motivated by his determination to preserve and develop the Gaelic language. The Gaelic language had been in decline for several centuries; the 1931 census registered 136,135 Gaelic speakers in Scotland, only 3% of the Scottish population. Despite his decision to write in the language, at times MacLean doubted that Gaelic would survive and his poetry would be appreciated.