NLtagger not filtering words such as "And, to, a, in"

what am I not understanding here. in short the view loads text from the jsons descriptions and then should filter out the words. and return and display a list of most used words, debugging shows words being identified by the code but does not filter them out

    private func loadWordCounts() {
        DispatchQueue.global(qos: .background).async {
            let fileManager = FileManager.default
            guard let documentsDirectory = try? fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) else { return }

            let descriptions = loadDescriptions(fileManager: fileManager, documentsDirectory: documentsDirectory)

            var counts = countWords(in: descriptions)

            let tagsToRemove: Set<NLTag> = [
                .verb,
                .pronoun,
                .determiner,
                .particle,
                .preposition,
                .conjunction,
                .interjection,
                .classifier
            ]

            for (word, _) in counts {
                let tagger = NLTagger(tagSchemes: [.lexicalClass])
                tagger.string = word

                let (tag, _) = tagger.tag(at: word.startIndex, unit: .word, scheme: .lexicalClass)

                if let unwrappedTag = tag, tagsToRemove.contains(unwrappedTag) {
                    counts[word] = 0
                }
            }

            DispatchQueue.main.async {
                self.wordCounts = counts
            }
        }
    }