Thank you. The code works.
The main difference I see from what I was trying is the tagSchemes on tagger creation. I was using NSLinguisticTagger.availableTagSchemes(forLanguage: "en"), which worked great when I am using the enumerateTags function, but seems to be a problem when using possibleTags.
enumerateTags is great at tokenization, but is fairly poor in tagging parts-of-speech in a sentence correctly, so I was looking to get the possible tags for each word to incorporate an older parser algorithm I created 10 years ago to parse the sentences using hints from enumerateTags to speed things up.
Thanks again.