Credit is due to the writers at ainm.ie of biographical entries.
Diarmuid Breathnach and Máire Ní Mhurchú are credited with the biographical sketch, in the original Irish/Gaelic, of Róisín Uí Thuama.

Continuing my quick-and-dirty translation of same:
[quote]
From the late 1940's she was extensively involved in the choral group, An gClaisceadal, which Séan Óg Ó Tuama directed every Saturday evening in the Royal Irish Academy of Music. She used to accompany the chorus, both on the harp and on the piano. She was present for hundreds of these performances, which featured established celebrities, such as Pádraig Ó Siochfhradha and Fionán Mac Coluim, as well as performers who would become famous in the 1960's, such as Mary O'Hara, Kathleen Watkins, and Éamon de Buitléar. In the 1950's, the show "Claisceadal an Radio" was broadcast by Radio Éirann. She also had her own program, "Rí-Rá agus Rabhcáin," and on the television series "Dilín Ó Deamhas," she played the role of Grandma / Mhamó.

Rósín Uí Thuama was a founding member of Cairde na Cruite from its inception in 1960, and at the time of her death she was the group's president [2005]. A woman harpist was a person of great importance in countries with Celtic cultural identities, and the musical key of the Irish harp was featured in countless concerts that she gave throughout those nations. Not surprisingly, with her background in Celtic languages, she was one of the vice-presidents of the Irish branch of the Celtic Congress.
An interesting detail is that one of her daughters, Róisín, married Dónall son of Micheál Ó Cuill of Cork, another person with a keen interest in Gaelic song.