Neil and sister Lilly Pearlman of Alba’s Edge perform at last year’s BCMFest in Harvard Square. (Photo: Jason Jong)

Irish, Scottish, Cape Breton and other Celtic music and dance are back in Harvard Square this weekend for the 12th annual three-day BCMFest.

The weekend starts with a 7 p.m. Friday “Roots & Branches Concert” looking at innovation in roots music (featured are the trio of Laurel Martin, Mark Roberts and Kieran Jordan; Flynn Cohen & The Deadstring Ensemble; and fiddler Jenna Moynihan) and an 8 p.m. Boston Urban Ceilidh that teaches and holds dances from the Irish, Scottish and Cape Breton traditions, all with live music.

Saturday brings a 10 a.m. to 5 p.m. Dayfest of songs, storytelling and other entertainment geared toward children and families, as well as participatory events such as Irish and Scottish music sessions and instruction in Scottish country dance. An early highlight of Dayfest: The return of  Scottish Fish, a fiddles-and-cello quintet made up of middle school and high school students.

Dayfest is followed at 7:30 p.m. by a BCMFest Nightcap Concert called “Women In Trad” and starring the all-female Celtic band Long Time Courting with Shannon Heaton, Liz Simmons, Val Thompson and Katie McNally and an assortment of guest musicians, dancers and storytellers performing selections that speak to the experiences of women through the ages:

With songs and tales of love and heartbreak, heroines and villains, daughters and mothers, supernatural beings and poets, and much more, “Women in Trad” will captivate long-time Celtic music lovers and general music enthusiasts alike.

Sunday is devoted to from noon to 5 p.m. to the BCMFest Academy, an afternoon of Celtic music classes taught by festival artists.

Events are at Club Passim, 47 Palmer St., First Parish Church, 3 Church St., and and Atrium location on the fourth floor of 50 Church St. The schedule and tickets – from $13 to $28 depending on which shows or combination of events are want – are here.