POS Tags Simplified

Keywords: #nlp #POS-tags



Part-of-Speech tagging is a very useful foundation of NLP and deeper NLP concepts. The action involves analysing text and returning the tokens of the text with the appropriate Part-of-Speech (POS) tags.

POS Tags

POS Tag Meaning Example
ADJ adjective super cat
ADP apposition my friend Liam
ADV adverb The boy ran quickly
AUX auxiliary He will make
CCONJ coordinating conjunction this and that
DET determiner the squirrel
INTJ interjection Oi!
NOUN noun the dog
NUM numeral one fork
PART particle not Sam ’s
PRON pronoun he shouts
PROPN proper noun Helsinki is beautiful
PUNCT punctuation Hello , there !
SCONJ subordinating conjunction I do this while they do that
SYM symbol 5 + 10
VERB verb They think that
X other this asd;lfkjasd;flkj

Source: Universal POS tags

Above is a list of the standardised POS tags. You will probably recognise many of them from English class.


Courtesy of Spacy’s visualiser (as always!), below I have included an example where the phrase “This is my house while I live here” has been analysed and POS tags have been assigned. You can see that the tags line up with what would be expected from the list above.

POS Tag Example

How Are POS Tags Assigned?

There are many different ways that POS Tags are assigned. These methods include dynamic programming algorithms (such as the popular Viterbi algorithm). It is common to see hidden Markov models implemented in POS-tagging algorithms. As with many modern NLP elements, machine learning is now very popular for POS-tagging. In this case, computers analyse corpora of text which has been appropriately tagged already and try to learn how to tag tokens itself.

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