The following is given by Zawahr Moir as an explanation in her book "Ismaili Hyms from South Asia: An Introduction to the Ginans" co authored with Christopher Shackle.
"'The thirty-six classes' are symbolic of the divided mass of the unregenerate who have turned a deaf ear to the Teaching, and are often contrasted with 'the thirty-three crores' of the saved. The verse from the Pir Shams Das Avatar: "varan chhatris aa(n)hi milo tetrisa" 'o thirty-six orders, here join the thirty three'.
Sur baaetali 'the forty-two tunes', a less commonly used symbolic number, presumably indicating the many ways in which the Teaching is presented through the ages. Within the community, the phrase is understood as 'teachings given in the thirty-six dialects and forty-two musical notes.'"
I understand the significance of 36 classes or dialects as meaning that the real understanding of the Ginans does not come through knowledge of the various dialects through which they are expressed, rather, it comes through obedience and devotion, i.e. tan man and dhan. Inspite of knowing all the 36 dialects one could still remain deaf to the Ginans.
From the Batini point of view, in an individual mehmani MHI has told an individual that he knows the language of birds! According to Ginans, Pirs have communicated with wild animals. The Pir being The Gur Bhrahma would know all.
From the Zaheri point of view, I think 36 dialects is just symbolic of many diverse languages and classes of people that he had preached to.
