Predicting words based on swiping a keyboard
To me it looks fine. Just some minor adjustments:

I think it would look even nicer if you defined constants for the magic numbers.

 const int AlphabetLength = 26;
 const int MinWordLength = 5;


In place of 97 I'd put simply an 'a'.



Instead of


currentPosition == -1



I suggest

currentPosition &lt; 0


The -1 looks like a magic number. I sometimes use a constant for it that I name IndexOutOfRange.



You use var everywhere but here :-)


int currentPosition = 0;





It might also be a good idea to move the code from the constructor into a new method like AddWords or AddWord so you can extend the dictionary later if necessary. Usually those dictionaries can learn new words.