I'd like to start by saying that your English is very good.  I will point out some words where I had difficulty understanding you, but those were the exceptions.  For the vast majority of your video, I understood you perfectly well.

0:16 "learner". You say this word too quickly.  This is a two-syllable word, so it should not be spoken as though it is a one-syllable word.  Slow it down, and pronounce each syllable.  (This might sound like I am being rude.  I don't mean to be.  I'm trying to give you a clear explanation.)

0:18 "boast of my English ability", or "boast about my English ability".

0:33 "we all can benefit from this audio". I *think* you said the word "audio" here.  If this was the word you were saying, your pronunciation was not correct.  This word has three syllables, so again you should say it slowly enough to pronounce each syllable correctly.  To provide phonetic hints: awe-dee-oh.

1:00 "among many different Chinese speeches".  The word 'speech' has two meanings.  It may mean the ability to communicate verbally (orally).  It may also mean a formal presentation, such as a headmaster giving a 'speech' to the whole school.  However, the plural 'speeches' only corresponds to the second meaning.  That is, 'speeches' is a collection of formal presentations, it does not refer to multiple forms of verbal communication. Therefore, I believe you should have used the word 'dialect' to refer to Mandarin, Shanghainese, and Cantonese as different versions of Chinese.

1:41 tongue clicking.  I have noticed in your audio presentations that you click your tongue when you are trying to remember a word.  Normally, I would not comment on this.  We *all* made sounds when we are trying to remember a word.  However, I know you are practicing your English for an important reason.  The problem with clicking your tongue is that it is a unusual sound.  It will draw the attention of your examiner, and highlights any break in fluency.  If possible, try saying 'ahh' or 'umm', because these are much more common and are less likely to be noticed.  Even better, try not to make a sound at all if you are remembering a word.  (I feel overly-critical making this point.  I'm truly not trying to "pick on" your speaking.  I'm truly trying to provide you with feedback.)

3:57 "these".  You say this word too quickly, and it sounds like 'this'.  Try to say it slightly slower, and emphasize the 'eee' sound that distinguishes 'these' from 'this'.

4:28 "these".  Here, you are providing an example of the 'th' sound in the word 'these'.  On this occasion, you say the word 'these' extremely well, because you are saying it a little more slowly.

5:19 "All the little girls ???? me into the hall".  Unfortunately, I don't know what you have said here.  I think you may have said 'calls', but that would be incorrect grammar.  So, if you said 'calls', then your grammar is incorrect (it would be, "All the little girls call me into the hall").  If you did not say 'calls', then your pronunication was not clear.

Because Italki places a limit on the length of corrections, I will post these first corrections now, and then start a new correction.

7:03 "Studying and studying; these two words".  Here you are talking about two similar words.  Unfortunately, both sounded like 'studying'.  I don't know what the other word was.

11:53 "but quite few diphthongs". The words 'quite few' do not represent an English phrase, because it would be an ambiguous phrase. You should say either of the following, depending on your meaning:

"it has quite a few diphthongs" ... if it has <em>many</em> diphthongs

"it has few diphthongs" ... if it has <em>few</em> diphthongs

12:09 "Mandarin".  You said this word too quickly.  Mandarin is a three-syllable word (man-da-rin), but you dropped the letter 'd' to make it something like a two-syllable word (mana-rin).

12:16 "has quite many diphthongs".  The words 'quite many' do not represent an English phrase. You can simply say, "has many diphthongs," or you can emphasize, "has very many diphthongs."

12:41 "discuss with someone from north China about a ????".  Unfortunately I did not understand this word.  Later I <em>think</em> you explained this word to be 'UFO'.  If so, 'UFO' is an acronym that should be pronounced as separate letters ('you-eff-oh').

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The video is 34 minutes, and to listen to it all, and to continue to make comments, would take me over an hour.  So I have stopped after listening to half of the video.  I hope that is enough to provide you with some feedback.

I want to reiterate that your English is very good.  With the few exceptions noted above, I had no difficulty understanding you.