Teaching English by playing word card

My boy's nursery closed for a week or so because of quarantine. It is a good time for having fun for both of us.

I decided to teach him few English words.

We bought a set of sixty cards with pictures, and started to learn these words.

For first two days boy memorized forty cards, and kept making mistakes in other twenty.

The process:

We did it during short 5-minute sessions, twice a day, at the morning and at the evening.

Two days after he memorized almost all, except only a few: city, field, sky.

It is an interesting story why they are special.

He had already known words like blue and green and when I showed him card with a green field, he said "green" and got stucked on continuation.

I call it "background issue".

We don't concentrate on mistakes, it will disappear over time.

One day after we changed the process, now he did it by himself:

He need not father anymore, but he is looking for approval, for compliment, you can see it on video how he always looks at me.

What is interesting in this:

1. He not only memorized all these cards, but also the history of them.
Those 20 which he had problem with I call "complicated" others "simple", and sometimes he pronounces the list name after the word.

2. If I hide one or two cards from the set, he always knows these cards and after he finished he asks me "where are <words from missed cards>".

3. Many cards for him not only a word, but a story. For instance after saying "food" he continues "Apple, Lemon, Juice etc", because I gave him these words as example of food.

How fast he memorized all these cards, and how easy it was for him - exceed all my expectations.
I already prepared forty more cards, but quarantine is over, so we will work on them once a day at the evening.