"On Eid al-Adha we don't go to school"
Translation:Iddi-el-hadj hatuendi shuleni
Why is an unexpected spelling HADJ used in the module? From https://sw.wikipedia.org/wiki/Idd_el_Hajj : "Idd el Hajj (pia: Idi el haji, eid el hajj) ni sikukuu ya Uislamu wakati wa mwezi wa Dhul Hijjah ambao ni mwezi wa Hajj. Sherehe hii inatunza kumbukumbu ya sadaka ya Ibrahimu."
This suggests the spelling should be HAJJ. The article continues for several paragraphs with details about this particular holiday.
EDIT: From Al Jazeera (edition of 26 Jul 2019): Saudi Arabia suspends Hajj visas for DR Congo over Ebola
I wouldn't necessarily consider any of Duo Swahili's spellings of Islamic holidays / holy days correct. You would do better (in my opinion) to seek authoritative outside sources. Of course you will still have to use Duo's (mis)spellings to get past these items, unless they correct them or at least allow for alternatives, which they have shown no inclination towards doing, despite years of my complaining about the issue.