YouTube
Exploiting the Google Natural Language API
https://www.youtube.com/watch?v=a4uDzQ6DBekNatural Language API - Google Cloud Python Tutorials p.4
https://www.youtube.com/watch?v=-13yIXiyFAs
Paid Service
Watson Natural Language Understanding
https://www.ibm.com/watson/services/natural-language-understanding/
api
Apache OpenNLP
https://opennlp.apache.org/
General
Top 22 NLP (Natural Language Processing) APIs for Developers in 2018 - Last Call - RapidAPI Blog
https://blog.rapidapi.com/best-nlp-api/A Simple Introduction to Natural Language Processing
https://becominghuman.ai/a-simple-introduction-to-natural-language-processing-ea66a1747b32