Read this: Catalan has inherited the typical vowel system of Vulgar Latin, with seven stressed phonemes: /a ɛ e i ɔ o u/, a common feature in Western Romance, except Spanish. Balearic has also instances of stressed /ə/. Dialects differ in the different degrees of vowel reduction, and the incidence of the pair /ɛ e/.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Where is this a common feature?
Western Romance