You can access this dialog via the menu entry Analysis \ Tools for Analysis \ N-Gram.
This dialog shows the list of the most frequent n-grams (the 1 to 5000 most frequent n-grams, depending on the input in the field Display of the [ ] most common N-Grams). You can select between histogram, digram, trigram and n-gram (4 <= N <= 16).
The button Determine list computes and sorts the n-gram list and displays it in a table:
The actual n-gram list can be transferred into the CrypTool main window via the button Save list.
By clicking the Text options button you can specify which alphabet is used during the analysis. N-grams that consist of non-alphabet characters are not shown in the table.