The Serbian vowel system is simple, with only five vowels.

The development of the vowel system remains subject to interpretation.

There are two possible ways to organize the Lithuanian vowel system.

Two different diachronic mechanisms may give rise to a vertical vowel system.

The vowel system closely resembles that of other Senufo languages.

This results in what is probably the most asymmetrical vowel system known.

The table below shows the two vowel systems, and several of the spelling systems that have been proposed.

The vowel system is the same as Spanish for most speakers.

Whitfield argued that the advocates for the recent vowel system had a wide variety of suggestions.

In what follows, we focus on one particular modern vowel system, that of Belfast vernacular.