Link your To-Do account and add tasks directly to your To-Do list without syncing through your Alexa lists.
This skill supports one-shot uses such as:
"Alexa, open Task Link add milk"
However, recognition performance of arbitrary words is substantially better when opening the skill first and then adding the item. For example,
"Alexa, open Task Link"
"add milk"
Along those lines the primary supported language to add a task is "add". Other reasonably natural alternatives are eschewed for the sake of peak recognition performance.