It’s a good question: Should I do my training in Turkish or in English?
The best way to answer that question is probably to ask yourself, “What do I ultimately want to be able to do?”
For example, if your ultimate goal is to give presentations in English, whether to visiting foreigners or at international conferences in other countries, you should probably do the training in English.
Yes, it will probably be harder that way, at least at the beginning.
However, when you’re done, you’ll be able to say to yourself proudly, “I took presentation training in English.”
And down the road, when your boss asks you to give a presentation in English, you’ll be a lot less nervous, because you’ll be thinking, “I did presentation training in English, and I lived to tell about it!”
And then, when you’re getting ready for those international conferences, you’ll want advanced training, and that training will be in English (because your presentation will be in English), and you’ll get more out of that training, because you will have already begun your training in English in the past.