When I write something in the jupyter notebook markdown field, the typos are not highlighted and often I ended up with something like this:
In almost all ID
The spellchecker and some other extensions from jupyter_contrib_nbextensions is incompatible with the ipython version 5.8.0. and later. (Found that it works in some cases for the version 5.0.0 [refer issue page of the same]. I'm not aware of its compatibility for the ipython versions between 5.0.0. to 5.8.0., please do comment if anyone knows).
The calico's nbextension 'spellchecker' available at https://bitbucket.org/ipre/calico/downloads/calico-spell-check-1.0.zip is an outdated version [dated 2015]. But calico had updated their nbextensions and made avaliable at the github repository [latest dated 2018]. It works fine for the ipython version 5.8.0.
Installation
git clone https://github.com/Calysto/notebook-extensions.git
cd notebook-extensions
jupyter nbextension install calysto --user
jupyter nbextension enable calysto/spell-check/main
Check its status:
jupyter nbextension list
When you now open or reload a notebook, there would be a new button visible with a check mark icon next to the button to open the command palette. You may click on it to check the spelling mistakes in the markdown cell.