The Dutch digraph ij originated from the same custom. Originally written ii, later ij, and pronounced as a long i (English "ee"), the sound later shifted to be similar to English "eye", see the Dutch names for the cities Berlijn and Parijs. Meanwhile, the long i sound is now written as ie. IJ is the only Dutch digraph that tends to be treated as a single letter and is capitalized as such. In education in the Netherlands it is taught as the 25th letter instead of y, which does not occur in native Dutch words, and in the phone book it used to be sorted together (mixed) with y. But since the advent of computers it is generally sorted as i followed by j. There are a few place names like Ysselsteyn where Y is pronounced as IJ.