This work reports development of a MIDI-to-Singing song synthesis that will produce audio files from MIDI data and arbitrary Romaji lyrics in Japanese. The MIDI-to-Singing system relies on the Flinger (Festival singer) for singing voice synthesis. Originally, this MIDI-to-Singing system was developed by English. Based on some Japanese pronunciation rules, a Japanese MIDI-to-Sing synthesis system was developed and derived. For a language transfer like Festival synthesized singing, two major tasks are the modifications of a phoneset and a lexicon. Originally, MIDI-to-Sing song synthesis can create singing voices in many languages, but there is no existing Japanese festival diphone voice available right now. We therefore used a voice transformation model in festival to develop Japanese MIDI-to-Singing synthesis. An evaluation of a song listening experiment was conducted and the result of this voice conversion showed that the synthesized singing voice successfully migrate from English to Japanese with high voice quality.