Mandarin Chinese Tone Three Sandhi (T3S) is a phenomenon where the first Tone 3 (T3, a falling-rising tone) syllable becomes a rising pitch when it is followed by another T3 syllable. The purpose of this study is to examine if the phonetically incomplete application of T3S among pseudowords could be reduced to the differences in articulatory implementation triggered by lexical familiarity effects. Four types of disyllabic T3 words were used, including two actual occurring morphemes (AO-AO), AO with an accidentally gapped morpheme (AO-AG), AG-AO, and AG-AG. Four acoustical parameters, including average fundamental frequency (f0), f0 contour, the turning percentage (lowest point) of the f0 contour and the f0 slope, were measured. Production results from thirty adult native speakers (with balanced gender) indicated that the application of T3S was phonetically incomplete for AG-AO and AG-AG word groups, showing that the morpheme type of the first syllable was the critical factor. Together with previous studies (Hsieh, 1970, 1975; Wang, 1993; Chuang et al., 2011; Wee, 2019), this study supported Zhang and Peng's (2013) view that the covert, phonetic contrasts observed between real words and certain pseudoword types can be attributed to differences in the articulatory implementation triggered by lexical familiarity effects.