15. A method according to claim 1 , further comprising: repeating: the extracting of a partial time series of first speech parameters {x i } p . . . q ; the extracting of a partial time series of second speech parameter vectors {Δ i } p . . . q ; the converting the partial time series of first speech parameter vectors and the partial series of second speech parameter vectors into a partial time series of third speech parameter vectors {y i } p . . . q ; and the synthesizing of a speech utterance from the time series of third speech parameter vectors; wherein each repetition is performed using a successive value of p.
1. A computer-implemented method for synthesizing a speech utterance, the method comprising: performing, by a processor, operations of: receiving an input time series of m first speech parameter vectors {x i } 1 . . . m , wherein: index i takes on values from 1 to m; each first speech parameter vector x i corresponds to an identically indexed one of m synchronization points, which are also indexed by i; each synchronization point defines at least one of a point in time and a time interval of the speech utterance; and each first speech parameter vector x i includes a first number n 1 of static speech parameters of a time interval of the speech utterance; preparing at least one input time series of m second speech parameter vectors {Δ i } 1 . . . m , wherein: each second speech parameter vector Δ i corresponds to an identically indexed one of the synchronisation points; and each second speech parameter vector Δ i includes a second number n 2 of dynamic speech parameters of a time interval of the speech utterance; extracting from the input time series of first speech parameter vectors {x i } 1 . . . m a partial time series of first speech parameter vectors {x i } p . . . q , wherein: p is the index of the first of the extracted first speech parameter vectors; q is the index of the last of the extracted first speech parameter vectors; and the partial time series of first speech parameter vectors {x i } p . . . q is a proper subset of the input time series of first speech parameter vectors {x i } 1 . . . m ; extracting from the input time series of second speech parameter vectors {Δ i } 1 . . . m a partial time series of second speech parameter vectors {Δ i } p . . . q , wherein: each vector Δ i of the partial time series of second speech parameter vectors corresponds to an identically indexed vector x i in the partial time series of first speech parameter vectors; converting the partial time series of first speech parameter vectors {x i } p . . . q and the partial time series of second speech parameter vectors {Δ i } p . . . q into a partial time series of corresponding third speech parameter vectors {y i } p . . . q , so as to: minimize differences between respective third speech parameter vectors y i of the partial time series of third speech parameter vectors {y i } p . . . q and their corresponding first speech parameter vectors x i of the partial time series of first speech parameter vectors {x i } p . . . q ; and minimize differences of dynamic characteristics between respective third speech parameter vectors y i of the partial time series of third speech parameter vectors {y i } p . . . q and their corresponding second speech parameter vectors Δ i of the partial time series of second speech parameter vectors {Δ i } p . . . q ; wherein the conversion of the partial time series of first speech parameter vectors {x i } p . . . q and the partial time series of second speech parameter vectors {Δ i } p . . . q is performed independent of converting any other first speech parameter vector {x i } 1 . . . p−1, q+1 . . . m ; and synthesizing a speech utterance from the time series of third speech parameter vectors {y i } p . . . q .