Languages can be divided into syllable-timed (where each syllable takes approximately the same amount of time and receives approximately the same amount of stress) and stress-timed (where the stressed syllables (longer, louder) fall at approximately regular intervals and the others are shorter and softer).
Many of my students speak syllable-timed languages, and tend to pronounce English in much the same way. The textbook and tests include sections on word stress, but I’m not sure that they understand it, or that I’m explaining it so that that can.
It doesn’t help that many English words have different stresses, for grammatical reasons, for example ex-PORT (verb) and EX-port (noun), or for British v American variety, for example of-FENCE (Br) and OFF-ence (Am) (some students from some countries watch American basketball).
One topic this week was health, fitness and beauty. One of the words in the test was massage. Some students underlined the first syllable and some the second. At the end of the test I wrote it on the board and said ‘How do you say this?’. Sure enough, the one who underlined the first syllable said MASS-age, and the others mass-AGE. And Dictionary.com backs them all up, giving muh-sahzh, –sahj or, esp. British, mas-ahzh. (I say, in their spelling, mas-ahj). The students who said mass-AGE are from the Philippines and Taiwan (more American influence) and the one who said MASS-age is Malaysian Indian (more British influence). (The answer book gives MASS-age – it’s a British English book.)
This morning my wife was watching Korean tv online. One segment was about an elderly man in Korea who speaks very good English but is obviously a foreigner speaking English. I shut my eyes and drifted off, then heard someone speaking Korean but who was obviously a foreigner speaking Korean. I looked and saw a young ?American man. How did I know, before I looked, that he was a foreigner speaking Korean? I haven’t heard enough foreigners speaking Korean to know what they sound like. With last night’s test in mind, I realised that he was applying stress-timing to Korean. To take a simple example, Koreans say an-nyeong ha-se-yo. Foreigners tend to say AN-nyeong HA-se-YO.