Edward would have spoken Gaelic at home, but learned to read and write in English at school. Gaelic was forbidden there, and he would have been beaten for speaking it to his friends at playtime.
From the 18th century until well into the 20th century, the British establishment thought Gaelic-speakers were uneducated and uncivilised. They thought that learning English would improve rural people’s lives.
In today’s world, where Gaelic is celebrated and officially supported, this is seen as having been utterly wrong. However, that was the environment young Edward Munro grew up in – when he scratched the name of the place where he lived into the stone he was doing the ‘right’ thing by translating baile (town, village, settlement) achadh (field) and droighinn (the blackthorn tree) into English as “Thornfield Manor”.