Hello ¶
,¶
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My name is Emma, and I am French and. I tried to practice my English to improve my written in English.

This format is similar to a letter, so add a comma after your introductory "Hello"

The first sentence seems to be a run-on sentence, so split it into two sentences.

So II've been learning English since myI was eight years old, but I have the feeling that I have never progressed because I have never practiced correctly.

But today I am motivated because I want to become bilingual.

Today it is the first time I used theis application and I already corrected two people who tried to learn French.

Hello ¶
, ¶
¶
My name is Emma,. I am French and I triedy to practice my English toand improve my written in English.

So I have learnt English since I was my eight years old but I have the feeling that I have never progress because I have never practiced correctly.

But todaynow I am motivate because I want to become bilingual.

Hello ¶
¶
¶
My name is Emma,. I am French and I triedam trying to practice my English to improve my written in Englishoutput in the language.

My name is Emma and I am French are two independent clauses, so you can’t separate them with commas. That’s what you call a comma splice. Also

Present= Habits
Present Progressive = Actions you’re doing right now that started in the past and that haven’t ended

As you can see, unlike French, you need the present progressive for your sentence.

So II’ve been learning English since myI was eight years old but I have the feeling that I have never actually progressed because I have never practiced correctly.

What do you mean by practiced correctly ? Then, progress is a noun, not a verb, to turn it into a verb you either add the -ed, or add an -ing if you’re taking about something you’re doing right now.
Example: I’m progressing my studies by attending extra classes.
Although, this one is not used a lot.
Also, so is a conjugation so it’s mostly used to connect sentences not start new ones.

But today I am motivI want to change thate because I want to become bilingual.

I added “I want to change that” to connect this sentence to the last one where you talked about never studying “correctly”. It makes more sense than yours since you never said what you were motivated to do.

Today ithis is themy first time I useusing the application and Ihave already corrected two people who tried toare learning French.

Application is shortened to app in everyday use. Then, This is my first time _____ is a pretty common structure to talk about doing something new. You can’t say “trying to learn”, it has to either be trying to speak or learning.