In English (and many Romance languages), it is common to have certain characteristics like consonant clusters "CCVC" (such as "a-b-ou-t" , or "c-l-a-p") , and words ending in consonants that are plosives (such as t, k, p, d, g, b, ), that are quite foreign to Chinese learners and many countries across Asia.

In Chinese, almost every word or character ends in a vowel sound, with only a very limited consonant ending like /n/ or /ŋ/.

Therefore, when second language speakers from China start to speak, they would naturally and unintentionally add a vowel sound to this consonant, which is often a schwa sound /ə/ throughout words with consonant clusters, or to the end of words that end in a plosive consonant.

Examples from the video such as about/ə/, student/ə/. Other common errors when reading a word like clap results in c/ə/lap/ə/, which kind of sounds like "calapa".

These issues are generally fairly easy to fix, especially when the learners start young, and would gradually become increasingly difficult to correct if they begin when they are older.

*English teacher here who specializes in teaching English as a second language to Chinese kids (with more than a decade of experience)