Variable syllabic boundaires, 10

10. The change of syllable-final //t// (thus in at#all, but not in a't+all) to [d] in regularly in North AmE and under conditions elsewhere) occurs if the following vowel is unstressed, regardless of the stress on the preceding nucleus;
e.g., formative ['ˈfɔrməɺɪv] flapped //t//

The syllabalization is seen to be especially relevant in the contrast between
lento : plato ['pleɪ tʰoʊ], motto ['mɒ tʰoʊ]
allegro: [pleɪd oʊ] [mɒd oʊ] cf. tap (with syllable-final [d]). In some lects, the change is to tap: ɺ

Italy, id'ly