There are separate callback functions available such as onAddWordToUserDictionary and onDeleteWordFromUserDictionary, that you can use to get information about newly added or removed words from the personal user dictionaries.

</script>
window.WEBSPELLCHECKER_CONFIG = {
    ...
    onAddWordToUserDictionary: function(word, instance) {
        console.log(word);
    },
    onDeleteWordFromUserDictionary: function(word, instance) {
        console.log(word);
    }
};
</script>

For the versions of the package before release 5.5.8, there is a temporary workaround available if you need to listen to Add or remove word actions performed by end users.

<script>
window.WEBSPELLCHECKER_CONFIG = {
    autoSearch: true,
    ....,
    onLoad: function(instance) {
        instance.subscribe('addWordToUserDictionary', function(data) {
            // Get the added `word` from `data.word` field
        });

        instance.subscribe('deleteWordFromUserDictionary', function(data) {
            // Get the deleted `word` from `data.word` field
        });
    }
};
</script>