Comment by int_19h

That's not really any different than the distinction (or lack thereof) between "ae" and "æ". For that matter, in Russian there is a letter "ы" which is historically a digraph consisting of two separately letters "ъ" and "i" that just happens to be treated as a single letter for so long that few people would even recognize it as a digraph. This kind of stuff is all language-specific, which is why for Worlde etc you always need to be aware of the context, and this context will then unambiguously decide what constitutes a single letter.