Chinese smartphone brands have often found themselves in hot water over restrictions on what you can do or type on them, thanks to built-in, system-level text filtering and censorship capabilities. Even third-party apps such as LINE have had to follow these censorship rules and block hundreds of words and phrases deemed sensitive or offensive in China, even though they are perfectly normal elsewhere.
It appears Apple also maintains such a list of filtered words, and tens of thousands of them are baked into its iPhone keyboard at the system level. However, these words and phrases are not outright blocked. You can still type them, but the autocomplete and swipe-typing systems automatically ignore them, so they never appear among the suggested words above the keyboard.
What exactly is Apple hiding in its iPhone keyboard?
Independent researcher Derik Kauffman detailed the discovery (via Swipe Blocked). A majority of the words are the usual suspects, related to violence, drugs, and overtly sexual themes. But a few other items are going to raise censorship concerns. For example, phrases like “dictator Trump” and “sleepy Joe,” both widely used in public political commentary, are on the keyboard’s gray list.
In a statement shared with Reuters, Apple did not offer a detailed explanation and only said the iPhone’s built-in keyboard is designed to avoid suggesting words that could be offensive or inappropriate.
But this odd behavior isn’t limited to words or themes related to the US. The predictive typing system in the iOS keyboard also blocks terms like “Tibetan independence” and “United Ireland,” as well as phrases that mock politicians, including Indian Prime Minister Narendra Modi and Leader of the Opposition Rahul Gandhi. Kauffman says that every major language supported by the iOS keyboard has some version of this invisible gray list, which Apple has never disclosed publicly.
How did researchers uncover Apple’s hidden word list?
Kauffman says he first suspected that such a gray list existed when he tried to swipe-type phrases like “bad boy” and “white man.” He then used OpenAI’s Codex and Anthropic’s Claude Code to dig into iOS, and eventually discovered thousands of words and phrases on the gray list.
Reuters’ own testing found that when you try to swipe-type “Tibetan independence” and “United Ireland,” the keyboard often changes them to “Tibetan independences” and “United Iceland.” Likewise, swipe-typing “white man” yields “white mean,” while “red man” and “blue man” go through without a problem.
The discovery is surprising, although not entirely shocking. Over the past few years, users have reported scattered instances of trying to type a word, only for the predictive system to refuse to comply. David Greene, a lawyer at the digital rights group Electronic Frontier Foundation, told Reuters that part of him found the list “creepy,” even though he could see the case for curbing inflammatory suggestions.