To judge the influence of speaker background on the quality of five long vowels and diphthongs /oU/, /eI/, /Au/, /EI/, and /2y/ in Standard Dutch, the spectra of these vowel realizations in spontaneous speech were measured for 70 subjects, and analyzed with regard to the subjects’ regions of education and residence, their level of education and occupation, as well as their sex and age. Our preliminary analyses indicated that high educated speakers lowered (higher F1, articulated more open) the long vowels and diphthongs and diphthongized them stronger than low educated speakers. There seemed to be effects of age but more data were needed to specify these. The new data show that besides the level of education or occupation, the factor ’age group’ has a major effect on the variations in speech production. The vowel attributes ’onset’ and ’degree of diphthongization’ were affected variably by speaker background data. Speakers of the older generation hardly differed in their realization behavior, contrary to the younger and middle aged speakers. The higher educated displayed systematic age patterns, the lower educated did not. A slight effect of region of residence was found for the females from the north peripheral residence region, who had higher onsets for /oU/. An effect of sex was found within the youngest age group, where higher educated males differed from higher educated females by their stronger diphthongization of /eI/ and /oU/. The vowel variations that were related to age reflected several pronunciation changes in progress.