Back in school time, we learned that the part of speech indicates the function of any word, like what it means in any sentence. There are commonly nine parts of speeches; noun, pronoun, verb, adverb, article, adjective, preposition, conjunction, interjection, and a word need to be fit into the proper part of speech to make sense in the sentence. 

#tutorial 

https://analyticsindiamag.com/complete-tutorial-on-parts-of-speech-pos-tagging/