Recently, I found something that I had no clue it existed in the English language. Recently, I found something that I had no clue existed in the English language.

If I am not mistaken, "that" is needed because "something" is the subject for "existed," rather than an object. We omit "it" in this type of phrase, for similar reasons.

Recently, I found something I had no clue it existed in the English language. Recently, I found something I had no clue existed in the English language.

Some time ago, I was wondering where commas should be put in the sentences. Some time ago, I was wondering where commas should be put in sentences.

You haven't specified a certain set of sentences, so you shouldn't use "the."

When I asked someone at the time, I was told to put it in places where I canould hear a pause in sound while reading it, and I believed it. When I asked someone at the time, I was told to put it in places where I could hear a pause while reading it, and I believed it.

"Hear a pause" already implies a pause in sound, so it sounds redundant. I would also change "it" to "that," but I think that it is acceptable as is.

When I asked someone at the time, I was told to put it in places where I can hear a pause in sound while reading it, and I believed it. When I asked someone at the time, I was told to put it in places where I can hear a pause while reading it, and I believed it.

At the time, I was used to adhering to the strict rules of the Czech language-, my mother tongue; nevertheless, I stopped searching for rules governing punctuation in English. At the time, I was used to adhering to the strict rules of the Czech language, my mother tongue; nevertheless, I stopped searching for rules governing punctuation in English.

"Strict rules" by itself is probably fine, but this makes more sense to me. My preference is to put a comma because you are not really emphasizing "my mother tongue" and an dash (—) would imply that to me.

At the time, I was used to adhering to strict rules of the Czech language-, my mother tongue; nevertheless, I stopped searching for rules governing punctuation in English. At the time, I was used to adhering to strict rules of the Czech language, my mother tongue; nevertheless, I stopped searching for rules governing punctuation in English.

Until yesterday, I followed an intuition rootstemming from what was ingrained in my mind from the countless years of studying English. Until yesterday, I followed an intuition stemming from what was ingrained in my mind from countless years of studying English.

You can say "stemming from" or "rooted in".

Even though I usually got it correct, it wasn't always the case. Even though I usually got it correct, it wasn't always the case.

This would probably be regarded as not incorrect by the average native speaker, but it sounds awkward to me. I would expect a more detailed main clause when "even though" has been used. Here, I would instead write, "I usually got it correct, but it wasn't always the case."

Even though I usually got it correct, it wasn't always the casebut not always. I usually got it correct, but not always.

In your sentence, "it" is being used twice, and the second "it" has no clear reference.

My last journal, "Act yourself into feeling", is an example of this. My last journal, "Act yourself into feeling", is an example of this.

I found out just yesterday about dependentsubordinate and independent clauses, and guess what;, it was here on lLangcCorrect whenre I found outlearned about them while reading corrections of other people's journals. I found out just yesterday about subordinate and independent clauses, and guess what, it was here on LangCorrect where I learned about them while reading corrections of other people's journals.

"Guess what" introduces something, so we can't end an independent on it. I changed "found out" to learned" to avoid repetition. Both verbs generally need an object. In certain situations, they can be omitted, but in my experience, that's mostly when what the object is is understood from context and when we are referring to actions or events.

I found out just yesterday about dependent and independent clauses, and guess what; it was? I found out right here on langcorrect when I found out while reading corrections of other people's journals. I found out just yesterday about dependent and independent clauses, and guess what? I found out right here on langcorrect while reading corrections of other people's journals.

For me, "when" didn't work following "here", but replacing "when" by "where" also didn't work because "while" implies time. So I moved "I found out" to the start of the sentence and added "right" for emphasis.

I noticed that even native speakers sometimes don't know these rules and use intuition as I did-—just like many people do in my mother tongue. I noticed that even native speakers sometimes don't know these rules and use intuition as I did—just like many people do in my mother tongue.

I noticed that even native speakers sometimes don't know these rules and use intuition as I did-just like many people do in my mother tongue. I notice that even native speakers sometimes don't know these rules and use intuition as I did-just like many people do in my mother tongue.

I would use present tense - "notice" instead of "noticed" - because this would be assumed to be an ongoing activity.