The nature of English Word Stress

Word stress is not used in all languages. Some languages, Japanese or French for example, pronounce each syllable with eq-ual em-pha-sis. Other languages, English for example, use word stress.
Word stress is your magic key to understanding spoken English. Native speakers of English use word stress naturally. Word stress is so natural for them that they don't even know they use it. Non-native speakers who speak English to native speakers without using word stress, encounter two problems: