Undecided questions
how many days does it take to learn taiwenese?

How many hours per day are you going to spend on studying Taiwanese? Are you already speak some Chinese? these are the major concern. Say 2-3 hours a day, for those who already speak Chinese will take months. For those who don't speak Chinese will take years.

In order to learn Taiwanese or any language you can follow 2 methods. First is the repetition-based method, where you learn Taiwanese words by writing them several times or saying them repeatedly until you remember them all. If you patiently follow the process, you will see your vocabulary extended very well.

Secondly, you also need have to have a notebook with your own note-taking rules. Each time you log onto Italki, note down any new words in the Questions and Answers section. The only problem is whether you want a rich vocabulary or not. Any good plan should answer the four following questions.

Firstly, how many words will you learn a week: five, ten, fifteen or more? Secondly, when will you learn them? At a fixed time every other morning or anytime you feel like learning?This is what I personally recommend. Thirdly, how often will you review what you have learnt: once a week, once a month or before a test ?
Finally, what areas of Taiwanese will you focus on: sports, music, games or sciences? The answers may vary a great deal from one person to another depending on memory, schedules and interest. Otherwise, your study results won't be as you expected. You can gain a big vocabulary and improve your Taiwanese by simply by determining what field of words to learn, making a plan of learning, choosing a learning method and regularly practising your plan and method. Although it is up to you, daily vocab learning is better than weekly and weekly is better than monthly. Good luck