This study aims to increase our knowledge about tone realization in disyllabic words in continuous Mandarin speech. Automatic alignments of large speech corpora were carried out to enable the study of potential tone variants, with a special focus on variation factors such as prosodic position and right tonal context. The alignments without tone variants (V0, phonological representation) show that Tone 4 is more frequent in phrase-final position than in other prosodic positions, supporting the "declination line" pattern often observed in speech production. Tone 4 is also the most frequent lexical tone (>50%) in all prosodic positions. Alignments permitting tone variants (V1, phonetic realization) show an increase of Tone 1 in phraseinitial position, compared to V0. Tone realization is observed to be related not only to the prosodic position, but also to the within-word right tonal context. Unsurprisingly, the most notable change in tone realization happens for Tone 3 in the first syllable of disyllabic words when followed by another Tone 3 because of the well-known "tone sandhi rule" in which T3T3 disyllabic words become T2T3. Crossword right tonal context is found to impact only Tone 3. However, the results in this study show that Tone 3 sandhi rule is more a tendency than an absolute rule.