It’s super expensive to maintain spontaneity in another language other than your mother tongue. 2 hours is needed everyday to avoid losing it (the spontaneity). Besides, it has to be your working language. Also, the atmosphere must be tolerant of your English speaking, rather than provoking a quiet hatred and xenophobia. Not easy at all.
But it’s still worth it. Acquiring spontaneity in English will help you grasp the notions and ideas super fast. That’s a great fortune to scholars.