T-Voks is an augmented theremin that controls Voks, a performative singing synthesizer. Originally developed for control with a graphic tablet interface, Voks allows for real-time pitch and time scaling, vocal effort modification and syllable sequencing for pre-recorded voice utterances. For T-Voks the theremin’s frequency antenna modifies the output pitch of the target utterance while the amplitude antenna controls not only volume as usual but also voice quality and vocal effort. Syllabic sequencing is handled by an additional pressure sensor attached to the player’s volume-control hand. This paper presents the system architecture of T-Voks, the preparation procedure for a song, playing gestures, and practice techniques, along with musical and poetic examples across four different languages and styles.