Hanyu Pinyin Spell-Check
This program checks words for correct Hanyu Pinyin. Please note that it does not check to see if the words truly exist in Mandarin, only if the spellings of their subsections are valid. Thus, for example, while aibicidibang isn't a real Mandarin word, its syllables all exist in Mandarin and it is not incorrectly formed; it would therefore pass as valid.
The only punctuation mark that can be included now is the apostrophe; I'll allow for additional punctuation in later versions.
It isn't programmed to allow for the retroflex -r typical of the Beijing accent.
Because people often forget to correctly use the apostrophe (which is needed in less than 2 percent of Mandarin words), this program will mark some problematic points unless you tell it not to.
For ü, use ü or v.