Some letters in the English language appear more often in the beginning of words. Some appear more often at the end, and others show up in the middle. Using the Brown corpus from the Natural Language Toolkit, David Taylor looked closer at letter position and usage.
I've had many "oh, yeah" moments looking over the graphs. For example, words almost never begin with "x", but it's quite common as the second letter. There's a little hump near the beginning of "u" that's caused by its proximity to "q", which is most common at the beginning of a word. When you remove "q" from the dataset, the hump disappears. "F" occurs toward the extremes, especially in prepositions ("for", "from", "of", "off") but rarely just before the middle.
Next step: letter proximity.