+"""Descriptive models of a natural language (in this case, English).
+
+The functions `Pwords`, `Pletters`, `Pbigrams`, and `Ptrigrams` return the
+log probability of a section of text.
+
+If you want to use a different language, replace the data files in
+[`szyfrow/language_model_files`](../language_model_files/index.html).
+
+* `count_1l.txt`: counts of single letters
+* `count_2l.txt`: counts of pairs letters, bigrams
+* `count_3l.txt`: counts of triples of letters, triagrams
+* `words.txt`: a dictionary of words, used for keyword-based cipher breaking.
+ These words should only contain characters cointained in
+ `string.ascii_letters`.
+
+"""
+