This study investigated the acoustic correlates of the four Mandarin tones in isolated words and variations in these parameters in relation to sentence environment, syllable vowel, and preceding consonant. Results indicate that differences associated with sentence environment, syllable vowel and preceding consonant affect the realization of the tone, although the four tones maintain their characteristic basic differences. The influence of sentence environment on tones is greater than that of the syllable vowel, and the influence of syllable vowel is greater than that of the preceding consonant.