When people are trying to learn English, they usually don’t realize how important the “music” (rhythm and intonation) are. This is an interesting video.
Are they speaking English?
How English sounds to non-English speakers
The people in it ARE NOT SPEAKING ENGLISH (so don’t be surprised if you can’t understand it). They are speaking nonsense. But the intonation and rhythm sound exactly like English.
Their voices rise and fall; their syllables are stressed and unstressed in the right pattern. But the words are not English.
For English learners–the best thing you can do is learn to use these intonation patterns and rhythmic patterns–but use real English words. Like magic you will begin to sound like a native speaker.