Mandarin is a syllable-based language, where rhythm is determined by the number of syllables and is largely even in stressing. Syllables on the whole don’t receive substantial stress differences to communicate. This can sometimes transfer to a native Mandarin speaker’s English, where stress and flow are essential to understanding. As a result, the speaker might stress English words evenly, mistakenly removing emphasis that supports understanding, or emphasizing words unessential to meaning. Some Mandarin speakers are found to stress the last word of an English phrase, regardless of its importance.
English’s stress-timed rhythm, where stress occurs at regular intervals with an inconsistent and changing number of unstressed syllables occurring in between, is an aspect of English speaking often not taught to native Mandarin speakers.
For beginning English-learners native to Mandarin, the flow in phrasing may be disrupted by the lack of stress/unstress variation, affecting intelligibility.
There are four distinct tones in Standard Mandarin (five if you count the “neutral tone”), which can sometimes carry over into English. It has been suggested that tones might be applied to English syllables according to the vowel’s placement.
In this short clip, notice the staccato, punchy rhythm and narrow range of pitch variety.