It is more important to understand descriptions or patterns of tendencies rather than rules. This is because rules only tell us what is true most of the time, and it is always possible to find exceptions. Learners should not simply memorize this information and consider it as always true. Rules are of some use, and are certainly worth studying at appropriate times, but they are not as important to memorize as to try to use them in real-time communication.
It makes sense for learners to discover patterns which are applicable and relevant to the language they are learning at a particular time, but always bear in mind that they are rules of thumb only. This list provides a ‘rough guide’ to stressed syllables.

Core vocabulary: Many ‘everyday’ nouns and adjectives of two-syllable length are stressed on the first syllable. Examples are: SISter, BROther, MOther, WAter, PAper, TAble, COFfe, LOvely etc.

Prefixes and suffixes: These are not usually stressed in English. Consider: QUietly, oRIGinally, deFECtive, and so on. (Note the exceptions, though, among prefixes, like BIcycle and DISlocate.)

Compound words: Words formed from a combination of two words tend to be stressed on the first element. Examples are: POSTman, NEWSpaper, TEApot and CROSSword.

Words having a dual role: In the case of words which can be used as either a noun or a verb, the noun will tend to be stressed on the first syllable (in line with the ‘core vocabulary’ rule above) and the verb on the last syllable (in line with the ‘prefix rule’). Examples are IMport (n),
imPORT (v); REbel (n), reBEL (v) and INcrease (n), inCREASE (v).

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