Neil Smith, 67, says Ginger, an English Cocker Spaniel picked up the language spoken mainly in the highlands and islands of western Scotland by responding to the words for sit (suidh), stay (fuirich), come here (trobhad) and good boy (cu math).
Mr Smith and the four-year-old canine have been attending weekly sessions at the Strone Church near Dunoon in Argyll and Bute along with 23 other people.
"He has given me a lot of confidence because I used to be a very shy person and often felt quite isolated in company, even with family and friends," said Mr Smith.
"Going to the Gaelic class gets me out and about to meet people, and I have always wanted to learn the language because my great-grandmother spoke it but it was not passed down through the family, so Ginger is helping to lead a family revival.
"Ginger has picked it up really quickly; it only took him about three weeks. It is great because I can show off that he is a bi-lingual dog - people think it is amazing that he can do that and it is a wee bit of added interest to the class."
"He is a very, sharp clever dog. It is a really good advert for Gaelic and I have never heard of a dog learning it as a second language before," said Elma McArthur, who teaches the class.
The Moderator of the General Assembly of the Church of Scotland, the Right Rev Dr Angus Morrison, added: "It is great to see an older person enjoying such a good relationship with his dog where Gaelic is the medium of communication," he added.