Challenges in NLP
Part-of-speech tagging. It is difficult to mark up terms in terms in a text as corresponding to a particular part of speech (such as nouns, verbs, adjectives, adverbs, etc.), because the part of speech depends not only on the definition of the term but also on the context within which it is used.
Text segmentation. Some written languages, such as Chinese, Japanese, and Thai, do not have single-word boundaries. In these instances, the text-parsing task requires the identification of word boundaries, which is often a difficult task. Similar challenges in speech segmentation emerge when analyzing spoken language, because sounds representing successive letters and words blend into each other.