How is word stress determined in English?

Stress in English is lexical, meaning that the stress is an important part of the meaning of the word. That means that words like REcord and reCORD are different words in English.

However, there are some patterns that you can learn that seem to hold true for certain morphemes in English.

And, stress moves in English to avoid stress clashes.

It's quite complicated, actually. E-mail me if you want to know more.

There may be be rules for what syllable of a word to emphasize, or as you said, stress, but I don't know what they are. I am a native English speaker, but I think Spanish is a much easier language to learn. Spanish has many more clear-cut rules of pronunciation, with accents over vowels to "overrule the rule" when necessary.

From country to country the English language will pronounce the very same words with the emphasis on a different syllable. One such example is "controversy". Americans say CONtroversy. Other countries say conTROversy. I say OBstacle. I have a friend from Oklahoma who says obSTAcle. Obviously there are few or no rules to help you. Sorry.

Unlike many other languages, the tonal quality of words in english carries subtext more than actually changing the nature of the word itself. Native english speakers stress a certain word differently to indicate mood, or to alert a listener to double/hidden meanings. It's very arbitrary and based on situation.