Student or Learner
Oh, how do you understand him? I don't hear anything. He is talking so fast.
You have spoiled my mood , now I'm thinkinkg that I'm uneducable.
Please, correct all my mistakes. I should know English perfectly and if you show me my mistakes I will achieve my dream a little bit faster. A lot of thanks.
Not a teacher nor a native speaker.
It sounded like "I've only did" to me too. The rest of that clip sounded relatively well-spoken (if rather fast) so I think, rather than being a bad grammatical choice on his part, he probably simply did what we all do - he started off planning to say "I've only done weight training" but halfway through the second word he thought "I only did weight training" might be better so he said "did". However, he'd already said "I've" so he ended up with three words which don't make a grammatically correct verb.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.