# Word frequency lists

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Language: Linguistics · Semiotics · Speech

In computational linguistics, a frequency list is a sorted list of words (word types) together with their frequency, where frequency here usually means the number of occurrences in a given corpus. A short example could be: </br> </br>

 the 3789654 he 2098762 [...] king 57897 boy 56975 [...] outrageous 76 [...] stringyfy 5 [...] transducionalify 1

It seems that Zipf's law holds for frequency lists drawn from longer texts of any natural language. Frequency lists are a necessary prerequisite for building of an electronic dictionary, which is by itself a prerequisite for a wide range of applications in computational linguistics.

German linguists define the häufigkeitsklasse (frequency class) $N$ of an item in the list using the base 2 logarithm of the ratio between its frequency and the frequency of the most frequent item. The most common item belongs to frequency class 0 (zero) and any item that is approximately half as frequent belongs in class 1. In the example list above, the misspelled word outragious has a ratio of 76/3789654 and belongs in class 16.

$N=\left\lfloor0.5-\log_2\left(\frac{\text{Frequency of this item}}{\text{Frequency of most common item}}\right)\right\rfloor$

where $\lfloor\ldots\rfloor$ is the floor function.