Which dictionaries are installed? Reply with the webpage and add-on version.

After downloading a UK dictionary, everything started working OK. Many thanks sfhowes!

my spell check is not working it is blank and wehen i type a wrong word it does not check it

mine is blank too

Mary said

my spell check is not working it is blank and wehen i type a wrong word it does not check it

Do you have check-as-you-type enabled in Tools/Options/Composition/Spelling? Which language is shown there? In Tools/Add-ons/Dictionaries, what is the dictionary and version?

english US yes i do

not in add ons i have nothing about dictionaries in the addons

Install this dictionary and see if it helps:

https://addons.thunderbird.net/en-US/thunderbird/addon/us-english-dictionary/

Right-click the Download Now button, Save link as..., download the xpi installer, Tools/Add-ons/Dictionaries in TB, click the gear icon next to search, Install Add-on from file..., select the xpi file.