A syllable consists of an onset, a non-y nucleus, and a coda. (A y-nucleus is excluded from the definition of syllable just for convenience, because y-syllables are not allowed in fu'ivla. y-syllables in brivla always have an empty coda).
An onset is an initial consonant or cluster, or a glide, or an h, or empty. (An empty onset can only appear at the beginning of a word, an h onset can never appear at the beginning of a word, a glide onset can never appear immediately after a diphthong).
A stressed-syllable, a stressed-diphthong and a stressed-vowel are, respectively, a syllable, a diphthong and a vowel with where the vowel is stressed ('A', 'E', 'I', 'O', 'U') or with stress being marked by being followed (possibly after intervening y and/or consonantal syllables) by just one syllable and then by a pause. (The use of capital 'I' and 'U' in glide position, or capital consonants, is not taken as a mark of stress).