One type of mistake sometimes made among non-native speakers (and indeed sometimes native speakers) is to not know which syllable the stress lies on when seeing the written form of a word.
And yes, there are a handful of cases of stress position being subject to variation (possibly more ideolectal than sociolinguistic). For example, the word "television" can be pronounced with the stress lying on either the first or last syllable; the word "cervical" can have the stress on either the first or second syllable, etc.
But, by and large, your underlying premise isn't true. Which syllable the stress falls on in an English word is generally determined by a fairly small number of factors (certain suffixes attract the stress in a particular position; certain vowels in certain positions tend to attract the stress over other vowels in other positions). The situation is a little more complex than, say, in Spanish. But it's by no means random or arbitrary.
Note that even in Spanish, there are cases of variation. Ask a group of people from different regions where they put the stress on "video", "periodo", or ask them how many syllables there are in the word "biólogo", and you're unlikely to get a consensus...