The dissertation project deals with the researching of vowel system in spoken Ukrainian standard language. The physical properties of vocalic sounds are investigated. This study characterizes the vowels of separate pronunciation as well as vowels of speech flow. Sounds are analyzed in various word positions and depending on speaking rate. The problem of speaking rate is solved: its nature, place and role in phonetic system is determined. The rate of Ukrainian speech is scaled experimentally on the slow, moderate and fast.