Are you using the Python port of SymSpell ?https://github.com/mammothb/symspellpy

By using CreateDictionaryEntry(“NewWord”,1) you may add any new word to the existing frequency dictionary. The defaultCountThreshold is 1. That means every word with a count≥1 in CreateDictionaryEntry is added as new word (if the word is not already contained in the dictionary)

If that does not work, the reason might be that the defaultCountThreshold has been set to a larger value than 1, when creating the SymSpell object. Make sure it is set to 1, or make sure the the word count in CreateDictionaryEntry is ≥ defaultCountThreshold.

Another possibility might be that there is a problem in the python port.