In this article, a methodology is presented regarding the design of a segment database for use with a time-domain speech synthesis system for the Greek language. The first step of this process is the generation of a corpus containing all possible instances of the segments for the specific language. Particular issues such as the phonetic coverage, the sentence selection (including factors such as type/origin and size) as well as iterative evaluation techniques employing custom-built tools are discussed. A methodology is then proposed which addresses quality control issues during the corpus-recording phase. Finally, a review is performed of the main features that need to be stored in the database for each segment. The aforementioned procedure allows for the fine-tuning of the segment database's language-dependent characteristics and thus assists in the generation of a high-quality text-to-speech synthesis system.