I am glad to see you in good spirits/in a good mood.. Does this phrase sound natural?

What do you mean/ What are you meaning What would you say about someones' English if they ask, "What are you meaning" instead of "What do you mean"? Does it sound natural?

a little mistake/ a small mistake Which word (little or small) can I use if I mention someone's minor mistake? Thank you in advance.

My Teacher I don't have another opportunity to say what I need to say...This entry is not supposed to be corrected so...don't correct it please. I got acquainted with Robert three years ago. He was among my first teachers on Italki. Since November 2018 I decided to focuse on studing English more seriously and I took lessons with Robert every week till the beginning of September. I have never thought we had something like an emotional connection with Robert but I really liked to talk to him. Every topic we discussed stuck in my mind and then I realised that I was seaching for new information about it... Our last lesson on September, 3 didn't happen and I was worried about it very much and checked Skype every 5 minutes. Now I know he passed away. I asked myself if I was a good student? Could I be more disciplined, or motivated or even polite? I wish I could be a better student. Thank you, Robert, for everything you gave me as a teacher. I will never forget you. Rest in peace, my dear teacher... I hope you are in a better place now. *Robert Bassford https://www.italki.com/teacher/1079372

The meaning of "green" when it is related to an unexperienced and/or naive person. Does it not imply that the person is supposed to be young as well? Could I say "green" about anyone who doesn't have much experience but not so young (middle-aged, for instance)? *I'd be happy to get answers from native English speakers

Do I need an article in such an expression: "with (a) visual impairment"? E.g., "people with disabilities (mostly with (a) visual impairment)" People with (a) hearing impairment.

How do I word it? Thanks in advance. At the games themselves, on (at?) registration, simply check the lists that you have thanks to pre-registration.

How many participants can there be? VS How many participants can be there? Which one is correct?

Don't make me confused VS Don't get me confused Which one is correct or more common?