It can be compared with a stress-timed language, where there is approximately the same amount of time between stressed syllables. Learners whose first language can be described as syllable-timed often have problems recognising and then producing features of English such as contractions, main and secondary stress, and elision.
Example
French is described as a syllable-timed language, English as a stress-timed one.
In the classroom
Activities which can help learners with recognition of these features of English include counting the number of words in a spoken sentence, sorting long words according to stress patterns, and dictation.
See also:
https://www.teachingenglish.org.uk/article/stress-timed
Further links:
https://www.teachingenglish.org.uk/article/stress-timing
https://www.teachingenglish.org.uk/article/connected-speech
https://www.teachingenglish.org.uk/article/rhythm