8. The method of claim 7 wherein: the act of interpolating a duration value for each phoneme using the duration weights further comprises the acts of: multiplying the predicted duration values predicted using each source voice font by the corresponding duration weight to produce weighted duration values; and summing the weighted duration values from each source voice font for each phoneme to produce an interpolated duration value for that phoneme; the act of interpolating a voiced/unvoiced probability value for each phoneme using the spectrum weights further comprises the acts of: multiplying the predicted voiced/unvoiced probability values predicted using each source voice font by the corresponding spectrum weight to produce weighted voiced/unvoiced probability values; and summing the weighted voiced/unvoiced probability values from each source voice font for each phoneme to produce an interpolated voiced/unvoiced probability value for that phoneme; the act of interpolating a f0 value for each phoneme using the f0 weights further comprises the acts of: multiplying the predicted f0 values predicted using each source voice font by the corresponding f0 weight to produce weighted f0 values; and summing the corresponding weighted f0 values from each source voice font for each frame to produce an interpolated f0 value for that frame; and the act of interpolating spectral trajectory value for each phoneme using the spectrum weights further comprises the acts of: multiplying the predicted spectral trajectory values predicted using each source voice font by the corresponding spectrum weight to produce weighted spectral trajectory values; and summing the corresponding weighted spectral trajectory values from each source voice font for each frame to produce an interpolated spectral trajectory value for that frame.
7. The method of claim 5 wherein the act of merging the predicted characteristic values with the corresponding weights further comprises the acts of: interpolating a duration value for each phoneme using the duration weights; interpolating an voiced/unvoiced probability value for each phoneme using the spectrum weights; making a voiced/unvoiced decision for each phoneme based on the voiced/unvoiced probability value for that phoneme; interpolating a f0 value for each phoneme using the f0 weight; normalizing the f0 values; and interpolating a spectral trajectory value for each phoneme using the spectrum weights.