This is one section of a long article by H. Heyoys, published in YIVO's filologishe shriftn in 1928, entitled 'Beliefs and customs in connection with death.' The study was based on a survey conducted among the members of the Vilna Teachers' Seminary in 1925, asking them about beliefs and customs in their own stetlekh. It also made use and intended to add to of a lot of secondary material, particularly the work of the pioneering female ethnographer Regina Lilientalowa. The 'L' here refers to her work. As in this example, Heyoys also sometimes refers to literary sources, here referring to the work of Isaac Meyer Dik in what appears to be an explanation for why professional mourning women were known in Yiddish as 'klogmuters.' It's a fascinating study, I've translated a few sections of it that talk about women's practices or beliefs relating to them, as here, in the section on lost souls, which lists some of the beliefs that made the work of a zogerke who can communicate with the dead so necessary.
Lost souls
Deceased mothers come at night and cry for their children. This is why they are called ‘klogmuters’ and ‘klogvayber’ (Isaac Meyer Dik)
On the yortsayt of their bodies and also in the month of elul, the soul stands on the grave and waits for visits from their close friends and relatives. Not visiting them at this time brings them shame and disgrace. The soul will also carry out the requests that are brought to it. (L, 18, 149.)
Before the wedding the bride and groom go to visit the graves of their deceased relatives, asking for forgiveness for all the evil they have done and inviting everyone to the wedding. The deceased parents indeed come to the wedding and bless the children. (L, 18, 264.)
On Yom Kippur the dead go to Kol Nidrei (Orle [the name of one of the towns studied.)
Source: H. Khayoys, ‘Gleybungen un minhogim in farbindungmitntoyt’, Filologishe shriftn, 2 (1928)