The sequences of adjacent vowels in any language evoke a complex problem, that views the quantity and the quality of the phonic elements the hiatus consists of. Pronouncing two vocalic sounds, there can be a pause between them as a result of the reduction of the air current intensity that comes out of the lungs. In this case those two adjacent vowels are separated in two different syllables, producing a vocalic continuity called hiatus. During the process of articulation, one of the vowels loses its syllabic character, being included into a single syllable, with a single muscular tension together with another vowel. During a thorough research it came out that in spoken languages sues a general predisposition of simplifying the act of communication. There is a wide spread tendency to avoid the hiatus through the introduction of a supporting element between those two adjacent vowels. In some situations, the supporting element is not only justified but also inevitable. The given article is a synthesized study of the conditions that favour the phenomenon of the phonic elements’ neutralization, the causes of devocalization, and the ways of hiatus avoidance.