 For example, in rapid speech the word "yläosa" ('upper part', from "ylä-", 'upper' + "osa", 'part') can be pronounced (with the diphthong ).The usual pronunciation is (with those vowels belonging to separate syllables).The diphthongs and are quite rare and mostly found in derivative words, where a derivational affix starting with (or properly the vowel harmonic archiphoneme ) fuses with the preceding vowel, e.g.