However, this approach would be insensitive to the phonological, syllabic and phrasal context that a word occurs in, which can have a large effect on word duration.
we use word duration estimates from the state-of-the-art open-source text-to-speech system MARY (Schröder et al., 2008, version 4.3.1), with the default voice package included in this version (cmu-slt-hsmm).