Substrings (Under Construction)

I'll zhuzh this up when I have the time. Basically I briefly got very interested in unusual letter combinations within words. Below are all of the two-letter combinations that appear in English words. Write a word in the input bar on the left side and press ENTER to fill in all the two-letter substrings of that word. If you're bored, see how many you can fill in!

Warning: right now code will take any string of letters as valid, so make sure you're entering a valid word! Also, the keyboard at the bottom doesn't do anything. Like I said, it's under construction.

If you're in a hurry, here are some quick challenges: