There's a lot of great freely available resources in NLP right now; and the field is moving quickly with the recent success of neural models. I wanted to mention a few that look interesting to me.
Jurefsky and Martin's Speech and Language Processing
The third edition is a free ebook that is in progress that covers a lot of the basic ideas in NLP. It's got a great reputation in the NLP community and is nearly complete now. It makes a good starting point or reference book for a particular subject.
Stanford CS224n: NLP with Deep Learning
This course covers Deep Learning from NLP in Pytorch and the 2019 video lectures are great. It's run by Chris Manning who is a leader in the field of neural chunking and parsing, and for example guided Stanza.
fast.ai NLP Course
Notable free resources
These all look good, but I would start with the above 3.
- Coursera NLP specialisation from deeplearning.ai in Tensorflow
- Training transformer from Huggingface with very popular transformer library
- NLTK Book good for the foundations in Python
- Yandex NLP Course including 2019 Jupyter notebooks (English), slides and lectures (Russian)
- CMU 2017 Neural NLP
- Oxford 2017 Deep NLP
- Eistenstein's NLP notes - very detailed!
- Various NLP Colab Notebooks
Also most Deep Learning courses will tend to touch on NLP, such as NYU 2020 Deep Learning with Pytorch.