Background
So I know plenty of Chinese words and grammar. I know loads, and due to the fantastic listening podcast SlowChinese, my listening is actually great. I'm so proud and happy.
I've contacted my teacher's students in China and when they speak Chinese over the phone, I can easily understand what they say. I can't respond with similar articulation and speed though.
I can say sentences that I have thought of prior to the conversation. I can't say sentences on the spot during the conversation. This is what I need to work on. Creating sentences as I go, being able to be more articulate. I have the grammar and vocabulary, it's just about speed. I need to speed up my brain.
Question
How can I develop the ability to speak faster and create complex sentences as I go, rather than spending 50 years thinking of them before I say them?
How can I practice being more articulate in conversations?
I should point out that I am able to say more simple sentences in Chines quickly on the spot, and create them easily, but when it is a complex and longer sentence I struggle. It's very hard for me to give in-depth views on something, thus limiting the things I can express.