What software or online tools can detect the parts of speech in a piece of written text (e.g. to predict if a word is a verb, adjective, etc.)?
I have had good results with the Stanford POS tagger.
There is a web demo system called ICTCLAS (Institute of Computing Technology, Chinese Lexical Analysis System). It was developed by the Institute of Computing Technology, Chinese Academy of Science.
There is also a web demo system from THULAS (Tsinghua University - Lexical Analyzer for Chinese), which was developed by the Nature Language Processing Group, Tsinghua University.
NOTE: I don't know (and I cannot test) whether these site can be accessed freely across the world.
NOTE2: As with any software language tool, take the results with a grain of salt, they aren't perfect.
There are many lexical analyzers for Chinese, but these are not developed for daily use, the typical usage is Chinese searcher engine.
I found 语言云 has a online demo, I test it by enter a sentence from today news,
The default result seems complicate, I deselected "语义依存分析" and "语义角色标注".
These tool can not be 100% accurate, for example, "选举" in the sentence is a noun, not verb ( so the SBV relation is also wrong, SBV means subject-verb), the biggest mistake is it split 因凡蒂诺(Sorry, Mr.Infantino) to 因 and 凡蒂诺.
These errors are understandable, it is still helpful.