Must the Friday khutbah be delivered in Arabic

Answer

This is the standard position of the four Sunni schools. According to the Shafi'i and Hanbali schools it applies only to the arkan (integrals) of the khutbah, though the arkan cannot be separated by lengthy non-Arabic speech or speech unrelated to them. Weaker positions in both the Shafi'i and Hanbali schools permit delivering the khutbah, even its arkan, in another language, and are practised in parts of the world, though it is more religiously cautious to follow the stronger positions. In more detail: the khutbah is analogically linked to the salah -- both are rituals to be performed as the Prophet, the khulafa, and the Companions practised them; the same need for non-Arabic speakers to understand existed then as now, yet no jurist or Companion adjusted the khutbah's language to meet it, which is itself evidence the khutbah should remain in Arabic. That the khutbah's purpose is understood to be teaching the people is a natural but unproven assumption -- like the Qur'an and the prayer's own adhkar, which are not translated for the sake of non-Arabic-speakers, the khutbah is also not translated. If comprehension were a condition of validity, an over-specialised khutbah nobody understood would have to be invalid, yet validity rests on the khatib delivering and the congregation hearing, not on comprehension. No scholar considers a pure Arabic khutbah invalid, while a vast number consider a non-Arabic one such -- so out of fairness to the majority position, Arabic should be used, with a short talk or reminder in the local language permitted before or after. No one should be condemned for following the weaker, still legitimate, position; good intentions must still be accompanied by correct action, and the difference of opinion here concerns the latter.