When Na'i becomes sick and the villagers won't help, Bashu performs a zar ceremony. Zar refers to an African belief that the body has been possessed by an evil wind, and in order to be cured, a ceremony involving drumming and chanting must take place to subdue the wind and return the afflicted to health. It was brought to Iran by Africans (many of them through the slave trade).
This was the first Iranian film to make use of the northern language of Iran, Gilaki, in a serious context rather than comic relief. Susan Taslimi who plays Na'i is Gilaki herself.
When the village boys are bullying Bashu and knock him to the ground he resolves the situation by grabbing a school book and reading an iconic, nationalist Persian line: "we are the children of Iran, Iran is our country." By doing so he demonstrates that he can read and understand the formal Persian, which is taught in schools. This is why he is also able to read and write the letters sent between Na'i and her husband.
Bashu, the Little Stranger was voted the "Best Iranian Film of all time" in November 1999 by a Persian movie magazine "Picture world" poll of 150 Iranian critics and professionals.
The character Bashu can not be understood by the Gilaki-speaking Northern Iranians as he speaks Khuzestani Arabic. This is a dialect of Gelet (Southern) Mesopotamian Arabic spoken by the Iranian Arabs in Khuzestan Province of Iran. It is only used in informal situations and is not taught in school.