(1962-1977): The first generation of speech synthesis featured a formant like synthesis of phonemes based on the phonetic breakdown of phrase to formant frequency contours which at that time was at the peak.
(1962-1977): The synthesis had low precision and naturalness due to the limited resources of that generation and was soon replaced by successors.
(1977-1992): In the second generation of speech synthesis the standards of intelligibility were improved with the immediate use of LCP parameters, however many would say that the lifelikeness of this process still remained low. This system relied on converting the appropriate units from text input to speech form.
(1992-present): This system can be customized to suit the given process, and uses “Unit Selection Synthesis” which according to a web based article were introduced to the public Sagisaka at ATR Labs in Kyoto. The latest version of this is available for American and British English, Danish, Finnish, French, German, Icelandic, Italian, Norwegian, Spanish, Swedish, and Dutch. Digital Equipment Corporation  (DEC) talk system is originally descended from MITalk and Klattalk and offers nine different voice personalities, four male, four female and one child (depending on the equipment). The present DECtalk structure is based on digital formant synthesis.