Word completion

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Word completion is a common feature in web browsers and similar text entry contexts. When a user begins the entry of a frequently-used word, the computer automatically completes it, or proposes a list of choices.

1 Successful example of word completion in browsers
2 Examples of word completion in general text editing
3 Examples of word completion
4 See also
5 References

[edit] Successful example of word completion in browsers

For an example of a relatively successful application of word completion, consider entering "www.microsoft.com" in the address box of a browser. A user may find that typing "www.mi" is sufficient. The completions database in use in this case is the user's browser history. "www.microsoft.com" would be a commonly offered completion. However, other completions may be available, with potential privacy implications, as this list may reveal the browsing history of other users of the computer. Similar problems may occur when word completion is used in predictive text systems as in the example identified by user:MeNext in a predictive text system ITAP marketed by Motorola, which uses word completion.

[edit] Examples of word completion in general text editing

Word completion can be ineffective for use in predictive text systems. Word completion works well only if there are a small number of possible items to search through. As discussed above, such is the case when entering urls in a browser. But for unrestricted text entry, word completion can be an impediment. A word-completion system requires that the user, after each keystroke, calculates whether it is better to keep on typing to decrease the size of the word-completion list, or examine the best choices presented to try to find their word. This mental effort is often ignored since it is much easier to think simply about counting keystrokes. However the effect of mental computation is real, and causes throughput to decrease rather than increase. Some early work in this area was done by Dunlop and Crossan ^[1].

The efficiency of word completion is based on the average length of the words typed.^{[citation needed]} If, for example, the text consists of programming languages which often have LongNamesForSpecialFunctions(), completion is both useful and generally applied in editors specially geared towards programmer such as Vim.

Consider for example entry of the word "soccer" with a word completion system, coupled to a reasonably large dictionary of English. This gives the following result:

	Type
	`s`	14,234 words begin with s,
	`so`	848 words begin with so,
	`soc`	75 words begin with soc,
	`socc`	2 words begin with socc

A user might reasonably guess that stopping at "soc" and then looking though a list of possible completions would find the word "soccer" more quickly than typing the rest of the letters, "cer". Unfortunately, this guess ignores many common words such as "sock" "socket" "society" "social", as well as uncommon words such as socorro or socrates.

In different languages, word lengths can differ dramatically. Picking up on the above example, a soccer player in German is translated as a "Fussballspieler", with a length of 15 character.

This example illustrates that English is not an ideal language for WC; this study[1] shows an average length for English words in a corpus of over 100,000 words to be 8.9, for Hungarian to be 10.5 and for German to be 13.2. In addition, in some languages like German called fusional languages as well as agglutinative languages, words can be combined, creating even longer words.

[edit] Examples of word completion

OpenOffice Writer has a working word completion program that proposes words previously typed in the text, rather than from the whole dictionary
The majority of programming directed text editors such as Vim have different levels of completion procedures