A unit inventory for concatenative speech synthesis in Brazilian Portuguese was built on the basis of an analysis of segment-prosody interactions. Segments are viewed as full or reduced depending on stress, syllable structure and phonological boundaries. Demisyllabic units preserve the integrity of segments reduced due to syllable structure. Intersyllabic units preserve the integrity of segments reduced due to stress and boundaries. Integrity of vowel clusters is also preserved, but nasal vowels and diphthongs are successfully concatenated to oral onsets. The resulting units were recorded in carrier words and sentences designed on phonotactic and grammatical grounds. Good quality concatenation is achieved even before the addition of prosodic treatment.