The cost of generating a corpus or an acoustic unit inventory is significant, because besides making the speech recordings, each recording has to be analyzed microscopically by hand to determine phoneme boundaries, phoneme labels, and other tags. Such time consuming analysis is not necessary for phrase splicing methods. A final consideration is size . Although the prices of memory and disk space are continually dropping, being able to have more channels on a given hardware platform translates directly into increased profits, and there is also an increasing interest in using speech synthesis on handheld devices. Thus, size still matters.
Concatenative synthesis has the edge on size.
Moreover, its quality limitations are less of a problem because the acoustic capabilities of handheld devices are themselves limited. In other words, each of these methods has problems with quality, scope, the amount of resources required, or size. Generating tools for the design , collection , and analysis of a large multi-purpose acoustic inventory that covers a range of common application domains, but also provides high quality speech for arbitrary input. Domain dependent intonation rules to generate substantially more natural intonation than can be obtained with general-purpose rules. Prosody GUI editing tool that allows generating optimal prosody for important phrases such as prompts and sentence frames.