Only two or three children at the 120-pupil Spittal VC primary speak Welsh as a first language, but thanks to Mrs Palmer's encouragement and guidance, many become so fluent that they invariably opt to go on to a Welsh-medium school for their secondary education.
"When I turned 60 last year I could have left," said Morwel, the first winner of the Assembly government award for the promotion of Welsh. "But because we have just moved into a brand new state-of-the-art building costing pound;2.1 million I did not want to go.
"Parents and staff here are extremely supportive and the children are absolutely fantastic."
The new-look Spittal school is a far cry from its predecessor, which dated back to the middle of the 19th century.
"There was one room with 60 pupils and three terrapin huts," Morwel remembers. "At one point, my headteacher Arthur Kendrick and I were teaching Years 2, 3, 4, 5 and 6 in that one room.
"The work was pretty challenging but also immensely rewarding, and the circumstances we found ourselves in taught the children to be flexible."
Mr Kendrick, who nominated his assistant head for the award, said: "What Morwel has achieved in this English-speaking area is nothing short of remarkable. I see my own role as facilitating what she can do. Her role is simply to get everyone to join in.
"I know better than anyone how much work she puts in. This is a new award and it's nice to think that Morwel's name is on it first."
Mother-of-two Mrs Palmer, who has drawn praise for her "natural and dynamic" approach in stimulating interest in Welsh language and culture, was brought up in a Welsh household in predominantly English-speaking Swansea, landed her first teaching job there in the 1960s, and subsequently moved to Pembrokeshire with her teacher-husband Bev.
A keen folk dancer away from the classroom, Morwel ensured that both her children were brought up to speak Welsh.
"I wanted them to speak the language so they would have that national heritage. That is also my attitude with my pupils."