Franklin Spelling Ace

The Spelling Ace expects you to be wrong. You type 'definately' or 'fonettickally' and the machine responds not with 'NOT FOUND' but with 'definitely' and 'phonetically'. That inversion — a lookup device whose whole value is guessing what you meant — is the HCI point, on a $90 keychain-sized consumer device in 1986, years before spell-checkers became standard in word processors and two decades before 'did you mean?' became the most-used feature on the web.

Proximity was co-founded in 1979 by Peter N. Yianilos and James H. Simons (who would go on to found Renaissance Technologies). Its contribution was a correction algorithm that modeled both how people misspell (phonetic substitutions) and how they mistype (adjacent keys, transpositions), then ranked candidate words from the Merriam-Webster-derived lexicon. US patent 4,830,618, 'Electronic spelling machine,' explicitly describes the pattern-matching functions: spelling validation, a mode listing all plausible corrections, and 'place indicia' wildcards that check an input word against every dictionary word with variables.

The '?' wildcard and the 'second-guess' key — showing words differing by one character, then two — are a manual version of edit-distance search: the machine relaxes the match one step at a time until the user recognizes the word. That is now a standard interaction in search engines; on the Spelling Ace it was shipped as a physical key labeled for a child.

The Spelling Ace debuted around $90, dropped to $70, and sold more than 800,000 units in its first two years — triggering Franklin's first profitable quarter since 1984 and a commemorated millionth speller on October 6, 1988. The line launched the 'handheld electronic book' category that produced Franklin's electronic dictionaries and the KJ-21 Electronic Bible (1989); by 1998 the company had sold more than 15 million handheld electronic books.