Apple maintains a “grey list” containing more than 100,000 words and phrases that its predictive text system will not autocomplete, according to independent researcher Derik Kauffman, who discovered the encoded list within the company’s operating system.
When users attempt to swipe-type—gliding a finger across the keyboard rather than tapping individual letters—these restricted words often fail to complete. For example, the phrase “United Ireland” may autocorrect to “United Iceland,” while “Tibetan independence” becomes “Tibetan independences.”
The list includes unsurprising categories: drug references, sexual acts, and phrases like “iMessage isn’t working.” However, it also contains phrases Kauffman characterized to Reuters as reflecting “light-touch censorship.” These include “Trayvon Martin” (the name of a Black teenager shot in Florida in 2012), “Kashmir dispute,” “Muslim extremist,” and “male chauvinist pig.” In Hebrew, Apple prevents autocomplete of “the occupied territories,” while in Arabic, it restricts “the Hamas movement.”
Kauffman, whose other work includes using AI to identify errors in scientific papers, discovered the list after noticing he had difficulty typing certain phrases on his iPhone while others worked normally.
Apple stated that it designed its keyboard to avoid offering “inappropriate or offensive” predictive suggestions. The company noted that iPhone users can always type out specific words or phrases manually and override predictive text suggestions to achieve their desired meaning.
The discovery offers insight into how autocorrect technology functions behind the scenes. Early versions relied on Unix operating systems that simply checked words against a dictionary. The technology evolved to use n-grams, which statistically predict the next word based on preceding words—the basis for Apple’s familiar autocorrect system, historically known for changing expletives into alternatives like “fork” and “ducking.”
Last year, Apple introduced a new “transformer-based” autocorrect system more similar to a large language model, which some Reddit users theorized explained unusual spelling suggestions they received. The grey list represents a more deliberate form of content control than these probabilistic systems, raising questions about what other invisible lists shape smartphone keyboards.
Key facts
- Apple has a ‘grey list’ of over 100,000 words and phrases restricted from predictive text completion
- The list was discovered by independent researcher Derik Kauffman in Apple’s operating system code
- Restricted words include drug references, sexual content, and political phrases like ‘Trayvon Martin’ and ‘Kashmir dispute’
- Users can still type these words manually but cannot use swipe-typing or autocomplete for them
- Apple says the restrictions are designed to avoid ‘inappropriate or offensive’ suggestions