User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

Language: English (Australia)
"taekwondo", or Taekwondo in any text input box.

Actual results:

comes up as a spelling mistake. When checking for correction, suggests "wonderland"

Expected results:

It should have recognised "Taekwondo" as valid in the English dictionary

"Taekwondo" is Korean, but has valid meaning internationally. Similarly, "Karate" is Japanese, but has come to have valid meaning internationally.

What made it stick out to me as a bug, is that the edit distance between "taekwondo" and "wonderland" is quite big.

The priority flag is not set for this bug.
:smaug, could you have a look please?

For more information, please visit auto_nag documentation.

This is more an issue with hunspell dictionaries. LibreOffice, as an example, shows the same issue.

This is either a duplicate of bug 1939561 (for tracking the work taekwondo), or a bug in Spelling Checker (because of the poor suggestion). Assuming is the latter, although I'm positive we have already bugs on file for that.

In that case now I'm confused when Spelling Checker: en-US Dictionary component should be used...

Uff, not sure how I picked Session Restore, thanks for correcting.

For missing or misspelled words in the en-US dictionary shipping as part of Mozilla desktop applications.

It was the right component for reporting a missing word, but I think this bug is more about the strange choice of suggested alternative.

Expected results:
It should have recognised "Taekwondo" as valid in the English dictionary

I think this is actually about a missing word. The title certainly is about suggestion, but there can't be a good suggestion without first having the correct word in the dictionary, so the root cause should the missing word.