The language has a system with five vowels in a stressed position , represented by a , e , i , o , and u and three ( two archiphonemes \/ I \/ , \/ U \/ and one phoneme \/ a \/ ) in non-stressed position , represented by e , u , and a at the end of word . Leonese language has a system with 5 vowels in a stressed position , represented a , e , i , o , u and three ( two archiphonemes \/ I \/ , \/ U \/ and one phoneme \/ a \/ ) in non-stressed position , represented with e , u , a at the end of word .