The Spanish vowels

Spanish has a very simple vowel system, comprising the following five vowels: [i], [e], [a], [o] and [u], as in piso ‘apartment’, peso ‘weight’, paso ‘step’, poso ‘sediment’ and puso ‘he/she put’.

In the production or articulation of a vowel, the body of the tongue arches upwards towards the roof of the mouth, its tip remaining at rest just behind the lower front teeth. The distinctive quality of any given vowel is a function of the tongue’s highest point in the mouth, as measured on both the vertical and the horizontal axes. Thus vowels are classed as being either high, mid or low, on the vertical axis, and as front, central or back, on the horizontal one.

Given this framework, the five vowels of Spanish can be presented schematically as in Table 1 below.

Table 1 The Spanish vowels



We see then that [i] and [u] are produced with the tongue relatively high in the mouth, [e] and [o] have an intermediate tongue height, and [a] is articulated with a fairly flat tongue. In terms of the horizontal axis, the table implies that [i] and [e] are produced with the tongue arching forward, [a] is associated with an intermediate position, and [o] and [u] are produced with the tongue arching backwards.


A vowel may also be specified in terms of whether the lips are rounded or unrounded during its articulation. If you reflect on the lip position for the vowel in the first syllable in each of piso, peso, paso, poso and puso, you should be able to notice that [o] and [u] are articulated with rounded lips, while the other three vowels have unrounded lips. As it turns out, the lip-rounding feature is not critical to the classification of Spanish vowels, as each of the five vowel sounds can be distinguished from the others in terms simply of its tongue height and its position on the horizontal axis.