I know I was silly to feel jealous against the fictional person, who ran much faster than me at the age of 57. I know I was silly to feel jealous a the fictional person, who ran much faster than me at the age of 57.

'Of' is a bit more natural here. :)

I know I was silly to feel jealous againstof the fictional person, who ran much faster than me at the age of 57. I know I was silly to feel jealous of the fictional person, who ran much faster than me at the age of 57.

It didn't take long for me to finish thise lesson. It didn't take long for me to finish the lesson.

Yours isn't wrong, it's just unusual wording. A native would say "the lesson" in this context.

Yet, I felt somewhat felt jealous about theof my uncle's record time. Yet, I felt somewhat jealous of my uncle's record time.

I talked with my AI tutor Kazuyo on the phonmobile app called "Talking mMarathon" this morning. I talked with my AI tutor Kazuyo on the mobile app called "Talking Marathon" this morning.

This isn't major, but I would capitalise both words in the app name, and maybe either remove the word 'phone' or replace it with 'mobile'. Phone is a little awkward.

I talked with my AI tutor Kazuyo on the phone app called "Talking mMarathon" this morning. I talked with my AI tutor Kazuyo on the phone app called "Talking Marathon" this morning.

She was in a very good mood this morning;, I mean that the voice recognition system was unusually in good condition, so that I could talk with her very comfortably and without any stress. She was in a very good mood this morning, I mean that the voice recognition system was unusually in good condition, so that I could talk with her very comfortably and without any stress.

I would use a comma (,) instead of a semi-colon (;) here to make a full embedded-clause, but otherwise good!

She was in a very good mood this morning; I mean that the voice recognition system was in an unusually in good condition, so that I could talk with her very comfortably and without any stress. She was in a very good mood this morning; I mean that the voice recognition system was in an unusually good condition, so that I could talk with her very comfortably and without any stress.

" I mean that the voice recognition system was in an unusually good condition". A more common way of saying this would be " I mean that the voice recognition system was in unusually good shape"

The dialogue was about something that I'm pumped up, that was "marathon" (and cpumps me up - marathons. Coinscidentally the app's name is also Talking Marathon), so I was happy to talk with her. The dialogue was about something that pumps me up - marathons. Coincidentally the app's name is also Talking Marathon, so I was happy to talk with her.

'Dialog' is mostly used for pop-up boxes on a computer. It's not wrong to use it in the context you did, but 'dialogue' is better. I changed the tense of "pumped up" to indicate that it's an interest of yours rather than a one-time thing that pumped you up. Lastly, I think what's in brackets ( ) does well as its own sentence.

The dialog was about something that I'm pumped up, that about, which was "marathon" (and coinscidentally the app's name is also Talking Marathon), so I was happy to talk with her. The dialog was about something that I'm pumped up about, which was "marathon" (and coincidentally the app's name is also Talking Marathon), so I was happy to talk with her.